Patent Description:
Current optical time of flight sensors employ photogate structures for redirecting photo-generated charge carriers in a semiconductor substrate to a read-out node for achieving time of flight information of an amplitude-modulated electromagnetic signal generated by a radiation source, wherein the electromagnetic signal is directed to an object and reflected to the time of flight sensor device.

However, the current design of optical time of flight sensor devices suffers from limitations of the quality of the sensor signal, i.e., on the efficiency of the transport of the photo-generated charge carries to the readout node(s), for achieving a good signal-to-noise ratio and a high temperature operability.

<NPL>) relates to the design and the characterization of a CMOS avalanche photodiode embedded in a phase-shift laser rangefinder and working as an photo-electronic mixer.

<CIT> relates to a high-speed light sensing apparatus. A switched photodetector converts an optical signal to an electrical signal. The switched photodetector includes a substrate, an absorption region, a first switch, a second switch, and a counter-doped region. The counter-doped region is arranged within the absorption region. The first and second switches are arranged on the absorption layer. The counter-doped region is a portion of the absorption region that has been doped with a dopant species to reduce a net carrier concentration of the absorption region. The absorption region is typically formed from semiconductor materials, such as Silicon , Germanium, or an alloy of the two, and has an associated intrinsic carrier concentration.

<CIT> relates to an optical semiconductor device and a method for manufacturing the same.

<CIT> relates to a stacked back side illuminated SPAD array.

<CIT> relates to a pixel and imager device having high-k dielectrics in the isolation structures.

Therefore, there is a need for improved optical time-of-flight sensor devices with an enhanced capability to convert the received optical signal in an electrical signal.

Such a need can be solved by the time of flight sensor device according to the independent claims. In addition, specific implementations of different embodiments of the time of flight sensor device are defined in the dependent claims.

Embodiments of the time of flight sensor device are described herein making reference to the appended drawings and figures.

Before discussing the present embodiments in further detail using the drawings, it is pointed out that in the figures and the specification identical elements and elements having the same functionality and/or the same technical or physical effect are usually provided with the same reference numbers or are identified with the same name, so that the description of these elements and of the functionality thereof as illustrated in the different embodiments are mutually exchangeable or may be applied to one another in the different embodiments.

In the following description, embodiments are discussed in detail, however, it should be appreciated that the embodiments provide many applicable concepts that can be embodied in a wide variety of semiconductor devices. The specific embodiments discussed are merely illustrative of specific ways to make and use the present concept, and do not limit the scope of the embodiments. In the following description of embodiments, the same or similar elements having the same function have associated therewith the same reference signs or the same name, and a description of the such elements will not be repeated for every embodiment. Moreover, features of the different embodiments described hereinafter may be combined with each other, unless specifically noted otherwise.

It is understood that when an element is referred to as being "connected" or "coupled" to another element, it may be directly connected or coupled to the other element, or intermediate elements may be present. Conversely, when an element is referred to as being "directly" connected to another element, "connected" or "coupled," there are no intermediate elements. Other terms used to describe the relationship between elements should be construed in a similar fashion (e.g., "between" versus "directly between", "adjacent" versus "directly adjacent", and "on" versus "directly on", etc.).

For facilitating the description of the different embodiments, the figures comprise a Cartesian coordinate system x, y, z, wherein the x-y-plane corresponds, i.e. is parallel, to the first main surface region of the semiconductor substrate, and wherein the depth direction vertical to the first main surface region and into the semiconductor substrate corresponds to the "z" direction, i.e. is parallel to the z direction. In the following description, the term "lateral" means a direction parallel to the x-direction, wherein the term "vertical" means a direction parallel to the z-direction.

<FIG> shows a schematic cross sectional view of a time of flight sensor device <NUM> according to an embodiment.

As shown in <FIG>, the time of flight (TOF) sensor device <NUM> comprises a semiconductor substrate <NUM>. The semiconductor substrate <NUM> for instance presents a generally rectangular cross-section along a vertical axis (i.e. in the depth direction or z direction). The semiconductor substrate <NUM> comprises a conversion region <NUM> to convert an electromagnetic signal "S<NUM>" in photo-generated charge carriers 114a, 114b, wherein the semiconductor substrate <NUM> further comprises a substrate doping region <NUM> having a n-doping type. The substrate doping region <NUM> extends from a first main surface region <NUM>-A of the semiconductor substrate <NUM>, which may form a top surface thereof, into the semiconductor substrate <NUM> (in the depth direction or z direction). The semiconductor substrate <NUM> may comprise silicon, germanium or any other semiconductor material. The semiconductor substrate <NUM> may comprise a bulk or epitaxially grown semiconductor material.

The remaining region <NUM>-<NUM> of the semiconductor substrate <NUM>-<NUM> adjacent to the substrate doping region <NUM> has a p-doping type. The substrate doping region <NUM> at least partially forms the conversion region <NUM> in the semiconductor substrate <NUM>. A readout node <NUM> is arranged in the semiconductor substrate <NUM> within the substrate doping region <NUM> and has the n-doping type, e.g. with a higher doping concentration than the substrate doping region <NUM>. The readout node <NUM> is configured to readout the photo-generated charge carries 114b, e.g., the photo-generated electrons. The photo-generated charge carries 114b (electrons) have the same type as the minority carriers in the substrate region <NUM>-<NUM>. The readout node <NUM> may be formed as an implanted doping region in the semiconductor substrate <NUM>.

The conversion region <NUM> is also referred to as absorption region in the semiconductor substrate <NUM> for receiving the electromagnetic signal S<NUM>, which is incident to first main surface region <NUM>-A of the semiconductor substrate <NUM>, and for generating electron-hole pairs (e/h-pairs). Thus, the portion of the incident electromagnetic signal S<NUM>, which enters the conversion region <NUM>, is at least partially converted into the photo-generated charge carriers 114a, 114b (e/h-pairs), wherein, for example, the negative charge carriers 114b (electrons) are shifted to the readout node <NUM>.

The TOF sensor device <NUM> further comprises a control electrode <NUM> which is arranged in the substrate doping region <NUM> of the semiconductor substrate <NUM> adjacent to the first main surface region <NUM>-A of the semiconductor substrate <NUM>. The control electrode <NUM> has the p-doping type. As shown in <FIG>, the control electrode <NUM> may optionally be further arranged in the conversion region <NUM> adjacent to the first main surface region <NUM>-A of the semiconductor substrate <NUM>. The control electrode <NUM> may be formed as implanted doping region in the semiconductor substrate <NUM>.

The TOF sensor device <NUM> may further comprise a substrate contact <NUM> which may be arranged at the p-doping type region <NUM>-<NUM> of the semiconductor substrate <NUM> adjacent to the substrate doping region <NUM>. The substrate contact <NUM> may be arranged, for example, to receive and discharge the positive charge carriers 114a, e.g. holes, photo-generated in the conversion region <NUM>. This may avoid a saturation of the semiconductor substrate <NUM> by positive charge carriers 114a (holes).

The substrate doping region <NUM> may comprise a n-type doping concentration (of doping atoms) in the range between 1E12 atoms/cm<NUM> and 1E16 atoms/cm<NUM>, or between 1E13 atoms/cm<NUM> and 1E15 atoms/cm<NUM>, for example. The substrate doping region <NUM> may extend between <NUM> and <NUM>, between <NUM> and <NUM>, or between <NUM> and <NUM> into the semiconductor substrate <NUM>, for example.

It should be noted that the formulation <NUM> EX atoms/cm<NUM> is intended to be equivalent to the formulation <NUM>X atoms/cm<NUM>.

The aspect ratio of the doping region <NUM>, that is the maximum vertical extension of the doping region <NUM> relative to a lateral extension of the doping region <NUM> may be between <NUM> and <NUM>, in some embodiments between <NUM> and <NUM> and in some embodiments between <NUM> and <NUM>.

According to an embodiment, the minimum doping concentration of the conversion region <NUM> is inside the n-doped substrate doping region <NUM>. The minimum mean or average doping concentration may refer to a minimum number of doping atoms (independent from their charge, therefore positive and negative) per cubic-centimeter.

The p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM> may comprise a p-type doping concentration (= substrate doping concentration) in the range between 1E12 atoms/cm<NUM> and 1E19 atoms/cm<NUM>, or between 1E14 atoms/cm<NUM> and 1E18 atoms/cm<NUM>, or between 1E15 atoms/cm<NUM> and 1E17 atoms/cm<NUM> for example.

The readout node <NUM> may comprise a n-type doping concentration greater than 1E14 atoms/cm<NUM> or in the range between 1E14 atoms/cm<NUM> and 1E22 atoms/cm<NUM>, or between 1E16 atoms/cm<NUM> and 1E21 atoms/cm<NUM>, or between 1E18 atoms/cm<NUM> and 5E20 atoms/cm<NUM>, for example.

The control electrode <NUM> may comprise a p-type doping concentration greater than 1E14 atoms/cm<NUM> or in the range between 1E14 atoms/cm-<NUM> and 1E22 atoms/cm-<NUM>, or between 1E16 atoms/cm<NUM> and 1E21 atoms/cm<NUM>, or between 1E18 atoms/cm<NUM> and 5E20 atoms/cm<NUM> for example. The implanted control electrode <NUM> may extend up to a depth of <NUM>, <NUM> or <NUM>,<NUM> into the semiconductor substrate <NUM>.

As shown in <FIG>, the substrate doping region <NUM> may laterally (in the ± x direction) extend beyond the conversion region <NUM> in the semiconductor substrate. In this case, only a part of the substrate doping region <NUM> contributes to the conversion region <NUM> in the semiconductor substrate <NUM>.

Furthermore, the conversion region <NUM> may vertically (in the z-direction or depth direction) extend beyond the substrate doping region <NUM> in the semiconductor substrate <NUM>, e.g., to the second main surface region <NUM>-B of the semiconductor substrate <NUM>. A bottom portion of the conversion region <NUM> is then formed by a portion of the region <NUM>-<NUM>.

According to a further embodiment, the entire substrate doping region <NUM> of the semiconductor substrate <NUM> may be part of the conversion region <NUM>.

The control electrode <NUM> in the substrate doping region <NUM> and adjacent to the first main surface region <NUM>-A of the semiconductor substrate <NUM> may be configured to provide, based on a control signal, an electrical potential distribution in the conversion region <NUM> and, thus, in the substrate doping region <NUM> for providing a phase sensitive or runtime-sensitive demodulation of the photo-generated charge carriers 114b in the conversion region <NUM>. Thus, the demodulation of the photo-generated charge carriers 114b may be achieved by means of a drift-based transport of the photo-generated charge carriers 114b to the respective readout node <NUM>. A controller (not shown in <FIG>) may apply the control signal to the control electrode <NUM>. Thus, the control electrode <NUM> is used to demodulate the photo-generated charge carriers 114b.

To summarize, one type of the photo-generated charge carriers, namely, the electrons 114b are demodulated by means of the control electrode(s) <NUM>, wherein the other type of photo-generated charge carrier, namely the holes 114a, is not demodulated but rather flows into the common substrate contact <NUM>.

According to an embodiment, a radiation source (not shown in <FIG>) generates an electromagnetic signal S<NUM>, which is amplitude-modulated by a modulation signal. The electromagnetic signal S<NUM> is directed to an object (not shown in <FIG>) and reflected to the time of flight sensor device <NUM>. Thus, the reflected portion S<NUM> of electromagnetic signal S<NUM> enters the conversion region <NUM> in the semiconductor substrate <NUM> and generates the photo-generated charge carriers 114a, 114b. During operation of the time of flight sensor device <NUM>, a demodulation signal (= the control signal), which is in-phase with a modulation signal or has a fixed phase relationship to the modulation signal, is applied to the control electrode <NUM>. The photo-generated charge carriers 114b, i.e. the electrons 114b, are directed to the readout node <NUM> depending on the demodulation signal applied to the control electrode <NUM> and based on the resulting electrical potential distribution in the substrate doping region <NUM>. The photo-generated charge carriers 114b directed to the readout node <NUM> are detected and a phase shift between the modulation signal and the electromagnetic signal reflected from the object and detected at the TOF sensor device may be determined, e.g. by a processing device or controller (not shown in <FIG>). Therefore, the time of flight of the electromagnetic signal S<NUM> and of the reflected portion S<NUM> of the electromagnetic signal S<NUM> may be determined from the detected photo-generated carriers 114b, which are provided at the readout node <NUM>. In other words, a mixing of the received electromagnetic radiation S<NUM> with the demodulation signal applied to the control electrode <NUM> is used to determine a time of flight information from the phase shift between the radiation emitted by the radiation source and the radiation received by the optical TOF sensor device <NUM>.

The substrate doping region <NUM> provides for an efficient demodulation even in vertical deep lying regions of the conversion region <NUM> and therefore the demodulation of the photo-generated charge carriers 114b is provided deep in the semiconductor substrate <NUM>. This in-volume demodulation avoids long path lengths and slow diffusive transport. A high electric field strength obtained provides for a fast extraction of the generated charge carriers 114b to the respective readout node.

According to an embodiment, the TOF sensor device <NUM> may optionally comprise a further control electrode <NUM>-<NUM> to optionally provide a pair of control electrodes <NUM>, <NUM>-<NUM> and a further readout node <NUM>-<NUM> to optionally provide a pair of readout nodes <NUM>, <NUM>-<NUM>.

The optional further control electrode <NUM>-<NUM> is also arranged in the substrate doping region <NUM> of the semiconductor substrate <NUM> and has the p-doping type. As shown in <FIG>, the further control electrode <NUM>-<NUM> may also be arranged in the conversion region <NUM> adjacent to the first main surface region <NUM>-A of the semiconductor substrate <NUM>. The further control electrode <NUM>-<NUM> may be formed as implanted doping region in the semiconductor substrate <NUM>. The further control electrode <NUM>-<NUM> may comprise the same p-type doping concentration as the control electrode <NUM>, for example.

In case, the further control electrode <NUM>-<NUM> is arranged in the time of flight sensor device <NUM>, the above description with respect to the functionality of the control electrode <NUM> is equally applicable to the further control electrode <NUM>-<NUM>.

The optional further readout node <NUM>-<NUM> is arranged in the semiconductor substrate <NUM> within the substrate doping region <NUM> and has the n-doping type, e.g. with a higher doping concentration than the substrate doping region <NUM>. The further readout node <NUM>-<NUM> is also configured to readout the photo-generated charge carries 114b, e.g., the photo-generated electrons. The further readout node <NUM>-<NUM> may be formed as further implanted doping region in the semiconductor substrate <NUM>. The further readout node <NUM>-<NUM> may comprise the same n-type doping concentration as the readout node <NUM>.

In case, the further readout node <NUM>-<NUM> is arranged in the time of flight sensor device <NUM>, the above description with respect to the functionality of the readout node <NUM>-<NUM> is equally applicable to the further readout node <NUM>-<NUM>.

Thus, the readout nodes <NUM>, <NUM>-<NUM>, and the control electrodes <NUM>, <NUM>-<NUM> can be arranged pairwise in the substrate doping region <NUM> and optionally in the conversion region <NUM> as well, wherein the pair of readout nodes <NUM>, <NUM>-<NUM> may be symmetrically arranged with respect to a symmetry line <NUM>-C (= on opposing sides of the center line <NUM>-C), which extends parallel to the z-direction, wherein the pair of control electrodes <NUM>, <NUM>-<NUM> may be also arranged symmetrically with respect to the symmetric line <NUM>-C (= on opposing sides of the center line <NUM>-C). Thus, the pairwise arranged readout nodes <NUM>, <NUM>-<NUM> may each have the same distance x<NUM> parallel to the x-direction from the center line (symmetry line) <NUM>-C, wherein further the pairwise arranged control electrodes <NUM>, <NUM>-<NUM> may each have the same distance x<NUM> parallel to the x-direction from the center line <NUM>-C.

The above described demodulation concept may be further applied to the pairwise arranged control electrodes <NUM>, <NUM>-<NUM> and pairwise arranged readout nodes <NUM>, <NUM>-<NUM> in that the photo-generated charge carriers 114b are directed to the first readout node <NUM> and subsequently to the second readout node <NUM>-<NUM> depending on the demodulation signal applied to the respective control electrode <NUM>, <NUM>-<NUM>. The photo-generated charge carriers 114b (e.g. the electrons) directed to the respective readout node <NUM>, <NUM>-<NUM> are detected and a phase shift between the modulation signal and the electromagnetic signal S<NUM> reflected from the object and detected at the time of flight sensor device <NUM> is derivable. Thus, a mixing of the received radiation S<NUM> with a demodulation signal is used to determine time of flight information from the phase shift between the emitted radiation S<NUM> from the radiation source and the radiation S<NUM> received by the optical time of flight sensor device <NUM>.

As shown in <FIG>, a further substrate contact <NUM>-<NUM> may be optionally provided at the p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM>. In case, the further substrate contact <NUM>-<NUM> is arranged, the above description with respect to the functionality of the substrate contact <NUM>-<NUM> is equally applicable to the further substrate contact <NUM>-<NUM>.

According to the embodiment of <FIG>, the control electrode <NUM> and the optional further control electrode <NUM>-<NUM> are formed as p-doping regions in the substrate doping region <NUM> having a n-doping type. Based on the control electrode <NUM>, <NUM>-<NUM>, a control signal (demodulation signal) applied to the respective control electrode <NUM>, <NUM>-<NUM> creates an electric field with relatively deep equipotential lines in the semiconductor substrate so that the demodulation of the photo-generated charge carriers can be extended relatively deep into the semiconductor substrate <NUM> and provides an efficient demodulation of the photo-generated charge carriers. This effect can be efficiently achieved as the at least one "implanted" control electrode <NUM>, <NUM>-<NUM> can extend relatively deep into the semiconductor substrate <NUM>.

As the at least one p-doped control electrode <NUM>, <NUM>-<NUM> of the optical time of flight sensor device <NUM>, as described with respect to <FIG>, is arranged in the substrate doping region <NUM> of the semiconductor substrate <NUM>, e.g. as implanted doping region, an absorption loss of the incident electromagnetic signal S<NUM>, which enters the conversion region <NUM>, may be avoided or at least reduced when compared to a control electrode design in form of metallization or polysilicon regions with an intermediate insulator layer on the main surface region <NUM>-A of the semiconductor substrate <NUM>.

Moreover, as the at least one p-doped control electrode <NUM>, <NUM>-<NUM> of the optical time of flight sensor device <NUM>, as described with respect to <FIG>, is arranged in the substrate doping region <NUM> of the semiconductor substrate <NUM>, e.g. as implanted doping region, a reduced leakage (shot noise) may be achieved. The leakage (shot noise) may result from electron/hole pair generation at the interface, e.g. a silicon-silicon dioxide interface at the first main surface region <NUM>-a of the semiconductor substrate <NUM>, and may be efficiently reduced by the design of the "implanted" control electrode(s) <NUM>, <NUM>-<NUM>. Thus, the time of flight sensor device <NUM> may provide a high signal-to-noise ratio (SNR) due to the reduced dark current from e/h pair-generation, for example, at an oxide interface inherent.

According to an embodiment, the optical time of flight sensor device <NUM> forms part of a device known as a pixel, which may further comprise further components, e.g. processing circuitry. This pixel itself forms part of a two-dimensional integrated pixel array for receiving optical visible or infrared radiation emitted by a light source and reflected by an object to be sensed, wherein the respective pixels provide an electrical output signal for determining a distance to the object by measuring the time-of-flight (travelling time) of the optical visible or infrared radiation. It should be noted that the time of flight sensor device <NUM> can be used in an apparatus comprising a single pixel, or within such an of an array of pixels.

As further illustrated in <FIG>, and whether in the corresponding embodiment or in any embodiment of the invention, optionally, the substrate doping region <NUM> extends to one or more side, i.e. lateral edge, of the sensor device <NUM> over at least part of the height of the sensor device <NUM>. For instance, it so extends only over part of the height of the substrate doping region. For instance, the p-doped region <NUM>-<NUM> comprises a portion located adjacent and beneath the substrate contact <NUM> and/or the further substrate contact <NUM>-<NUM>. Alternatively, the substrate doping region <NUM> extends to the main surface region <NUM>-A in the vicinity of the corresponding lateral edge of the sensor device <NUM>.

For instance, the side or sides of a given sensor device <NUM> to which the substrate doping region <NUM> extends is a function of a location of the considered sensor device <NUM> within the pixel array.

For a non-edge sensor device <NUM>, i.e. a sensor device <NUM> having no lateral edge forming an outer boundary of the array, the substrate doping region <NUM> may extend to all the lateral edges of the sensor device.

For an edge sensor device <NUM>, i.e. a sensor having one or more lateral edge forming an outer boundary of the array, the substrate doping region <NUM> may not extend to the corresponding lateral edge(s) of the sensor device <NUM>, and the corresponding lateral edge(s) is formed by the material of the p-doped region <NUM>-<NUM>.

Within the array, two neighboring sensor devices <NUM> may be in contact with each other laterally, in which case their respective substrate doping regions <NUM> may be in contact with each other in the region of the lateral edges of the sensor devices <NUM>.

Alternatively, neighboring sensor devices <NUM> within the array may not be in contact with each other.

In some embodiments, whether that of <FIG> or any other, on one or more side of the sensor device <NUM>, the region <NUM>-<NUM> is arranged so as to form of a wall stretching over the entire span of the side of the sensor device <NUM>. It may stretch vertically over the entire height of the sensor device, or only over part of it, in which case the substrate doping region <NUM> may extend to the side of the sensor device above the region <NUM>-<NUM>.

<FIG> shows a schematic cross sectional view of the time of flight sensor device <NUM>, wherein the drawing plane is parallel to the y-z-plane (= perpendicular to the drawing plane of <FIG>). As shown in <FIG>, the region <NUM>-<NUM> is arranged so as to form of a wall stretching over the entire span of the side of the sensor device <NUM>.

However, alternatively, the region <NUM>-<NUM> is arranged so to as form a plurality of vertical columns with gaps therebetween. The substrate doping region <NUM> then extends to the corresponding side of the sensor device <NUM> between the gaps formed between the columns, as schematically shown in <FIG>.

On the sides of the sensor device <NUM>, the matter of the region <NUM>-<NUM> may be formed e.g. by epitaxial growth or by implantation, whether in a same process step as the remainder of the region <NUM>-<NUM>, or in a prior or subsequent step.

In the following, a number of different possible implementations of the time of flight sensor device <NUM> are exemplarily described.

In the present description of embodiments, the same or similar elements having the same structure and/or function are provided with the same reference numbers or the same name, wherein a detailed description of such elements will not be repeated for every embodiment. Thus, the above description with respect to <FIG> is equally applicable to the further embodiments as described below. In the following description, essentially the differences, e.g. additional elements, to the embodiment as shown in <FIG> and the technical effect(s) resulting therefrom are discussed in detail.

<FIG> shows a schematic cross sectional view of an optical time of flight sensor device according to a further embodiment.

As shown in <FIG>, a sensor electrode <NUM>, e.g. a so-called separation gate or photogate (modulation gate), which is optionally separated by an isolating material <NUM> form the semiconductor substrate <NUM> may be arranged on the first main surface region <NUM>-A of the semiconductor substrate <NUM>. As shown in <FIG>, the sensor electrode <NUM> may be arranged in a lateral direction between the control electrode <NUM> and the readout node <NUM>. The sensor electrode <NUM> may be configured to modify, based on a further control signal applied thereto, an electric potential distribution in the substrate doping region <NUM>, e.g. between the control electrode <NUM> and the readout node <NUM>. The sensor electrode <NUM> may provide a capacitive decoupling of the control electrode <NUM> and the readout node <NUM> to prevent crosstalk or biasing from the control electrode <NUM> to the readout node <NUM>.

According to an embodiment, the sensor electrode <NUM> may be arranged on the first main surface region <NUM>-A of the semiconductor substrate <NUM> laterally neighboring the at least one readout node <NUM>. The sensor electrode <NUM> may support retaining the collected or directed charge carriers even in case the potential applied to the control electrode <NUM> is removed. To this end, a constant potential, e.g., a constant positive voltage in case of an n-type substrate doping region <NUM>, may be applied to the further control electrode <NUM>. The amplitude of the potential applied to the further control electrode <NUM> may be less than the amplitude of the reverse voltage applied to the readout node <NUM> but may be higher than the maximum potential applied to the control electrode <NUM>.

As shown in <FIG>, the time of flight sensor device <NUM> may optionally comprise the further control electrode <NUM>-<NUM> and the further readout node <NUM>-<NUM>, wherein a further sensor electrode <NUM>-<NUM>, which is separated by an isolating material <NUM> from the semiconductor substrate <NUM>, may be arranged on the substrate doping region <NUM>, e.g. laterally between the further control electrode <NUM>-<NUM> and the further readout node <NUM>-<NUM>.

In case the further control electrode <NUM>-<NUM>, the further readout mode <NUM>-<NUM> and the further sensor electrode <NUM>-<NUM> are arranged in the time of flight sensor device <NUM>, the above description with respect to the functionality of the sensor electrode <NUM> in view of the control electrode <NUM> and the readout node <NUM> is equally applicable to the further sensor electrode <NUM>-<NUM> in view of the further control electrode <NUM>-<NUM> and the further readout node <NUM>-<NUM>.

To summarize, as shown in <FIG>, a sensor electrode <NUM> may be provided on the first main surface region <NUM>-A of the semiconductor substrate <NUM> in combination with the control electrode <NUM> for redirecting the photo-generated charge carriers to the readout node <NUM>.

Moreover, the further sensor electrode <NUM>-<NUM> may be optionally provided on the first main surface region <NUM>-A of the semiconductor substrate <NUM> in combination with the further control electrode <NUM>-<NUM> for redirecting the photo-generated charge carriers to further readout node <NUM>-<NUM>.

Moreover, further sensor electrodes <NUM>-<NUM>,. , may be provided on the first main surface region <NUM>-A of the semiconductor substrate <NUM> for redirecting the photo-generated charge carriers to respective readout node <NUM>, <NUM>-<NUM>.

Based on the combination of the at least one control electrode <NUM>, <NUM>-<NUM> with the at least one sensor electrode <NUM>, <NUM>-<NUM>, <NUM>-<NUM>,. (e.g. a separation gate electrode or photogate electrode), an efficient demodulation of the photo-generated charge carriers in the conversion region <NUM> is achieved.

<FIG> shows a schematic cross sectional view of the time of flight sensor device <NUM> according to a further embodiment.

As shown in <FIG>, the time of flight sensor device comprises the control electrodes <NUM>, <NUM>-<NUM> and the associated readout nodes <NUM>, <NUM>-<NUM>. Further, the substrate contact <NUM> and, optionally, the further substrate contact <NUM>-<NUM> are provided. As shown in <FIG>, a further doping region <NUM> having a p-doping type may be arranged between the control electrodes <NUM>, <NUM>-<NUM> in the substrate doping region <NUM> adjacent to the first main surface region <NUM>-A of the semiconductor substrate <NUM>. The further doping region <NUM> forms a surface pinning layer and may be formed by implantation of dopants at the first main surface region <NUM>-A of the semiconductor substrate <NUM>. The pinning layer <NUM> as well as the at least one control electrode <NUM>, <NUM>-<NUM> may be formed as implanted doped regions, e.g. during the same implanting step.

The pinning layer <NUM> may comprise a p-type doping concentration greater than 1E14 atoms/cm<NUM>, such as between 1E14 atoms/cm<NUM> and 1E18 atoms/cm<NUM>, or between 1E15 atoms/cm<NUM> and 1E17 atoms/cm<NUM>, or between 5E15 atoms/cm<NUM> and 5E16 atoms/cm<NUM>, for example.

Thus, the pinning layer <NUM> in form of a p-doped resistive region of the semiconductor substrate <NUM> adjacent to the first main surface region <NUM>-A and between the two control electrodes (demodulation electrodes) <NUM>, <NUM>-<NUM> is configured to suppress or at least reduce a leakage current generation in the semiconductor substrate <NUM> adjacent to the first main surface region <NUM>-A thereof. The doping concentration of the resistive pinning layer provides for a high resistivity, so that a low or suppressed leakage (shot noise) from electron/hole pair generations at the first main surface region <NUM>-A of the semiconductor substrate <NUM>, i.e., at the semiconductor/oxide interface, may be achieved. Thus, the transport of the photo-generated charge carriers ( electrons) 114b from the conversion region <NUM> to the respective readout node <NUM>, <NUM>-<NUM> may be spatially kept away from the regions of the semiconductor substrate <NUM> directly adjacent to the first main surface region <NUM>-A.

<FIG> shows as schematic cross sectional view of the time of flight sensor device <NUM> according to a further embodiment.

The time of flight sensor device as shown in <FIG> may be implemented as described with respect to <FIG>, wherein the time of flight sensor device <NUM> further comprises a buried doping layer <NUM> in the semiconductor substrate <NUM>. Thus, the above description with respect to <FIG> is equally applicable to the further embodiments as described below.

The time of flight sensor device <NUM> comprises a semiconductor substrate <NUM> comprising a conversion region <NUM> to convert an electromagnetic signal S<NUM> in photo-generated charge carriers 114a, 114b, and comprising a substrate doping region <NUM> having a n-doping type, wherein the substrate doping region <NUM> extends from a first main surface region <NUM>-A of the semiconductor substrate <NUM> into the semiconductor substrate <NUM>. The semiconductor substrate <NUM> has adjacent to the substrate doping region <NUM> a p-doped region <NUM>-<NUM>. The substrate doping region <NUM> at least partially forms the conversion region <NUM> in the semiconductor substrate <NUM>. At least one readout node <NUM>, <NUM>-<NUM> arranged in the semiconductor substrate <NUM> within the substrate doping region <NUM> and having the n-doping type, wherein the at least one readout node <NUM>, <NUM>-<NUM> is configured to readout the negative charge carriers 114b. At least one control electrode <NUM>, <NUM>-<NUM> is arranged in the substrate doping region <NUM> of the semiconductor substrate <NUM> and in the substrate doping region <NUM> and having the p-doping type.

The buried doping layer <NUM> is arranged in the semiconductor substrate vertically (in the z-direction) below the substrate doping region <NUM> and the p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM>. The buried doping layer <NUM> may, for example, extend to the second main surface region <NUM>-B of the semiconductor substrate <NUM>. The buried doping layer <NUM> may be a part of the p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM>. The buried doping layer <NUM> has a higher p-type doping concentration than the p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM> adjacent to the substrate doping region <NUM>.

As shown in <FIG>, the conversion region <NUM> extends into the buried doping region <NUM>, wherein a portion of the buried doping layer <NUM> contributes to or is part of the conversion region <NUM> in the semiconductor substrate <NUM>.

According to a further embodiment, the complete buried doping region <NUM> may be part of the conversion region <NUM>.

According to a further embodiment (not shown in <FIG>) the buried doping layer <NUM> may be arranged in the semiconductor substrate <NUM> in the z-direction directly adjacent to the substrate doping region <NUM> in the semiconductor substrate <NUM>. Thus, the buried doping layer <NUM> may also form the p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM>.

As shown in <FIG>, the buried doping layer <NUM> is formed in the semiconductor substrate <NUM> vertically below in the depth direction (z-direction) the substrate doping region <NUM> and, for example, vertically offset in the depth direction of the semiconductor substrate <NUM> to the substrate doping region <NUM>.

<FIG> shows two exemplary alternatives I, II of the doping profile D<NUM> of the buried semiconductor layer <NUM> in the depth direction (= z-direction) of the semiconductor substrate <NUM>.

As shown in <FIG>, according to a first alternative "I" of the doping concentration D, the buried doping layer <NUM> has a continuously (or monotonically) increasing p-type doping concentration D<NUM>-<NUM> starting at the depth z<NUM> (= at the plane parallel to the x-y-plane at the depth position z<NUM>) with a first doping concentration D<NUM> up to a maximum doping concentration D<NUM>.

According to a second alternative "II" of the doping concentration D, the buried doping layer <NUM> provides a graded doping profile in the semiconductor substrate <NUM> below the substrate doping region <NUM>. The graded doping profile "II" has a maximum doping concentration D<NUM> of the p-doping type in an intermediate region at the depth z<NUM> (= at a plane parallel to the x-y-plane at the depth position z<NUM>) of the buried doping layer <NUM>. Thus, the buried doping layer <NUM> comprises an exponentially decreasing doping concentration D<NUM>-<NUM> from the intermediate region z<NUM> of the buried doping layer <NUM> in the depth direction to the second main surface region <NUM>-B.

The doping concentration D<NUM> may comprise a p-type doping with a doping concentration up to 1E15 atoms/cm<NUM> or 1E12 atoms/cm<NUM>, for example.

The doping concentration D<NUM> may comprise a p-type doping in the range between 1E17 atoms/cm<NUM> and 1E20 atoms/cm<NUM>, or between 5E17 atoms/cm<NUM> and 5E19 atoms/cm<NUM>, for example.

The doping concentration D<NUM> may comprise a p-type doping in the range between <NUM>. 1E15 atoms/cm<NUM> and 1E20 atoms/cm<NUM>, or between 5E17 atoms/cm<NUM> and 5E19 atoms/cm<NUM>, for example.

The doping concentration D<NUM> may comprise a p-type doping in the range between 1E12 atoms/cm<NUM> and 1E18 atoms/cm<NUM>, or between 1E14 atoms/cm<NUM> and 1E17 atoms/cm<NUM>, for example.

The buried doping layer <NUM> may comprise typical or minimum thickness t<NUM> in the range between <NUM> and <NUM>, or between <NUM> and <NUM>, for example.

In case, the buried doping layer <NUM> extends to the second main surface region <NUM>-B of the semiconductor substrate <NUM>, the thickness t<NUM> of the buried doping layer <NUM> may be up to <NUM> or <NUM>.

The buried doping layer <NUM> according to alternative I or II provides a drift field for minority carriers drifting the photo-generated electrons in the direction of the main surface and towards the substrate doping region <NUM>.

Moreover, the graded doping profile according to alternative II of the buried doping layer <NUM> provides a electrostatic barrier for photo-generated charge carriers generated in semiconductor regions of the semiconductor substrate <NUM> extending in the depth direction beyond the depth position z<NUM> of the buried doping layer <NUM> having the maximum doping concentration D<NUM>. Thus, photo-generated charge carriers 114a, 114b in deeper regions of the semiconductor substrate <NUM> laterally diffuse and do not affect or negatively influence the demodulation of the photo-generated charge carriers in the substrate doping region <NUM>. Thus, the p-type buried doping layer <NUM> effectively suppresses or at least reduces that "slow" (diffusing) charge carriers photo-generated in deeper regions of the semiconductor substrate <NUM> reach the substrate doping region <NUM>.

Moreover, the at least control electrode <NUM>, <NUM>-<NUM> in the n-doped substrate doping region <NUM> provides in combination with the p-doped buried doping layer <NUM> an effective electrical drift field for the photo-generated charge carriers 114b (electrons) in the substrate doping region <NUM> for a drift-based transport of the photo-generated charge carriers 114b to the respective readout node <NUM>, <NUM>-<NUM>.

Based on the pin-junction between the p-doped buried doping layer <NUM> (or the p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM>) and the n-doped substrate doping region <NUM>, the electrical drift field for the photo-generated charge carriers extend in relatively deep regions of the substrate doping region <NUM>.

To summarize, based on the p-doped buried doping layer <NUM>, a relatively slow diffusion of photo-generated charge carriers to the surface <NUM>-A of the semiconductor substrate <NUM> can be suppressed or at least reduced, which charge carriers would otherwise adversely affect the resulting demodulation contrast.

Moreover, the graded doping profile I, II of the buried of the doping layer <NUM> as shown in <FIG> provides for an effective drift field for the photo-generated charge carriers 114b so that the sensitive volume, i.e. the demodulation volume with photo-generated charge carriers constructively contributing to the sensor output signal, can be increased, and a fast charge carrier extraction can be achieved.

Furthermore, according to the graded doping profile of the second alternative shown in <FIG>, slow, e.g. diffusing, charge carriers can be rejected by the downward grading of the doping profile (beyond the depth position z<NUM>) towards the substrate backside <NUM>-B, i.e., the second main surface region <NUM>-B of the semiconductor substrate <NUM>.

As exemplarily shown in <FIG>, the control electrode(s) <NUM>, <NUM>-<NUM> of the time of flight sensor device <NUM> may arranged in the substrate doping region <NUM> of the semiconductor substrate <NUM> and may have the p doping type, e.g. as an implanted p doping region in the semiconductor substrate <NUM>. Thus, the control electrode(s) <NUM>, <NUM>-<NUM> of the time of flight sensor device <NUM> may correspond to the control electrode(s) <NUM>, <NUM>-<NUM> of the time of flight sensor device <NUM> (e.g. as described with respect to <FIG>).

Alternatively, the control electrode(s) <NUM>, <NUM>-<NUM> of the time of flight sensor device <NUM> may be arranged on the substrate doping region <NUM> of the semiconductor substrate <NUM> and may be separated by an insulating material <NUM> from the semiconductor substrate, e.g. in form of a metallization or polysilicon region <NUM>, <NUM>-<NUM> with an intermediate insulator layer <NUM> on the main surface region <NUM>-A of the semiconductor substrate <NUM>
<FIG> shows a schematic cross sectional view of the time of flight sensor device <NUM> according to a further embodiment.

The time of flight sensor device as shown in <FIG> may be implemented as described with respect to <FIG>, <FIG> wherein the time of flight sensor device <NUM> further comprises a trench structure <NUM> in the semiconductor substrate <NUM>. Thus, the above description with respect to <FIG> and <FIG> is equally applicable to the further embodiments as described below.

The time of flight sensor device <NUM> comprises a semiconductor substrate <NUM> comprising a conversion region <NUM> to convert an electromagnetic signal S<NUM> in photo-generated charge carriers 114a, 114b, and comprising a substrate doping region <NUM> having a n-doping type, wherein the substrate doping region <NUM> extends from a first main surface region <NUM>-A of the semiconductor substrate <NUM> into the semiconductor substrate <NUM>. The semiconductor substrate <NUM> has adjacent to the substrate doping region <NUM> a p-doped region <NUM>-<NUM>. The substrate doping region <NUM> at least partially forms the conversion region <NUM> in the semiconductor substrate <NUM>. At least one readout node <NUM>, <NUM>-<NUM> arranged in the semiconductor substrate <NUM> within the substrate doping region <NUM> and having the n-doping type, wherein the at least one readout node <NUM>, <NUM>-<NUM> is configured to readout the photo generated charge carriers 114b. At least one control electrode <NUM>, <NUM>-<NUM> is arranged in the substrate doping region <NUM> of the semiconductor substrate <NUM> and in the substrate doping region <NUM> and having the p-doping type.

Furthermore, the time of flight sensor device <NUM> according to the main embodiment comprises a trench structure <NUM>, which is configured e.g. to suppress or at least reduce cross-talking between adjacent sensor devices <NUM> within the array.

The trench structure <NUM> extends vertically in the sensor device. According to an embodiment, it presents a spatial arrangement which is symmetrical relative to a central axis of the device. This central axis is for instance defined as a vertical axis (stretching along the z direction) passing through the middle of the segment between the readout nodes <NUM> and <NUM>-<NUM>.

<FIG> shows a schematic cross sectional views of the time of flight sensor device <NUM>, wherein the drawing plane is parallel to the x-y-plane (= perpendicular to the drawing plane of <FIG>).

For instance, the trench structure <NUM> presents a cross-section along a vertical axis of the sensor device <NUM> which is generally quadrilateral, such as diamond-shaped, rectangular or square.

The trench structure may be arranged so that the sides of its quadrilateral cross-section are parallel to the sides of the sensor device, see <FIG> - options <NUM> and <NUM>. In such a configuration, the trench structure is for instance arranged in the periphery of the sensor device <NUM>. The trench structure <NUM> may consist of a single continuous trench, see <FIG> - option <NUM>. Alternatively, it comprises a plurality of trenches at a distance from each other and which each stretch along a side of the quadrilateral shape of the trench structure <NUM>, see <FIG> - option <NUM>.

Alternatively, the trench structure <NUM> is rotated relative to the sides of the sensor device <NUM>, for instance by <NUM>°. For instance, the sides of the cross-section of the trench structure <NUM> stretch along planes intersecting the middle of a face of the sensor device <NUM> and the middle of a neighboring face, see <FIG> - options <NUM> and <NUM>. The trench structure <NUM> may consist of a single continuous trench, see <FIG> - option <NUM>. Alternatively, it comprises a plurality of trenches at a distance from each other which each stretch along a side of the quadrilateral shape of the trench structure <NUM>, see <FIG> - option <NUM>.

The trench structure <NUM> is arranged laterally with respect to all or part of the substrate doping region <NUM>.

The trench structure <NUM> may border at least a portion of the lateral side face <NUM>-A of the substrate doping layer <NUM>. In other words, it may be arranged in the semiconductor substrate to at least partially or completely laterally surround or enclose the substrate doping region <NUM>.

In the example of <FIG>, the trench structure <NUM> is arranged directly adjacent to a lateral side face <NUM>-A of the substrate doping region <NUM> over all or part of the height of the substrate doping region <NUM>. Thus, in the corresponding locations, the substrate doping region <NUM> may completely extend between the opposing portions of the laterally arranged trench structure <NUM>. In such a configuration, the at least one substrate contact <NUM>, <NUM>-<NUM> may be arranged as a back side contact at the second main surface region <NUM>-b of the semiconductor substrate <NUM> or may be laterally arranged in contact with the p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM> (not shown in <FIG>).

The trench structure <NUM> may form an outer edge of the sensor device <NUM> over part of the circumference of the later. The trench structure <NUM> is buried in the semiconductor substrate <NUM>.

As shown in <FIG>, the trench structure <NUM> may extend within the semiconductor substrate <NUM> to or into the p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM> all the way to a bottom surface of the sensor device <NUM>. Alternatively, it ends at a distance from the bottom surface <NUM>- B of the sensor device <NUM>.

Moreover, the trench structure <NUM> ends at a distance from the first main surface region <NUM>-A. The substrate doping region <NUM> may thus extend to the lateral edge of the sensor device <NUM> above the trench structure, and optionally between the trench structure <NUM> and the first main surface region <NUM>-A.

The inner volume of the trench structure <NUM> may be filled with a dielectric material or may comprise an empty space (void or gas), for instance so as to cause Total Internal Reflections of the light incident upon the trench structure <NUM>.

In some embodiments, whether that of <FIG> or any comprising a trench structure <NUM>, the trench structure <NUM> may be provided with a liner <NUM> surrounding all or part of the trench structure <NUM>. The liner <NUM> may vertically extend over the entire portion of the trench which is located laterally relative to the substrate doping region <NUM>.

The liner <NUM> may extend from the p-doping region <NUM>-<NUM>. Alternatively, the liner <NUM> may extend into the p-doping region <NUM>-<NUM>.

The liner <NUM> acts as an outer boundary for the corresponding region of the trench. The liner <NUM> may encapsulate the trench structure <NUM> in the region in which the liner <NUM> is present. Alternatively, the liner <NUM> may only border some of the sides of the trench structure <NUM>.

The liner <NUM> is for instance configured to act as a pinning layer.

The liner <NUM> is made of p-doped material. The liner <NUM> may be made of the same material of the p-doping region <NUM>-<NUM>, or a different material.

The liner <NUM> may be grown epitaxially, may be formed by out-diffusion (e.g. from an oxide or gas initially arranged in the trench), or by implantation.

In the following, a number of different possible implementations of the time of flight sensor device <NUM> having the trench structure <NUM> are exemplarily described. The different configurations, in particular in terms of structure and geometry of the trench structure <NUM>, described in reference to <FIG> apply to these implementations.

<FIG> shows a schematic cross view of a time of flight sensor device according to an example not covered by the claims.

As shown in <FIG>, the trench structure <NUM> is laterally spaced from the substrate doping region <NUM>, i.e. from the lateral side face <NUM>-A of the substrate doping region <NUM>, wherein at least a part of the p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM> extends between the substrate doping region <NUM> and the trench structure <NUM>.

As shown in <FIG>, the trench structure <NUM> is laterally spaced from the substrate doping region <NUM> by means of the p-doped semiconductor region <NUM>-<NUM> of the semiconductor substrate, i.e., the trench structure <NUM> and the substrate doping region <NUM> are not directly adjacent. Based on this implementation, a crosstalk between neighboring sensor cells of the time of flight sensor device <NUM> may be suppressed or at least reduced. Furthermore, the distribution of the electrical potential within the substrate doping region <NUM> may be improved for providing a fast charge carrier transport to the at least one readout node <NUM>, <NUM>-<NUM>.

As shown in <FIG>, the at least one substrate contact <NUM>, <NUM>-<NUM> may be arranged at the first main surface region <NUM>-A (front side) or at the second main surface region <NUM>-B (back side) of the semiconductor substrate <NUM> in electrical contact with the p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM>.

One notes that the embodiment of <FIG> can be seen as an embodiment of <FIG> in which the trench structure <NUM> borders the device <NUM> at least in part and wherein the liner <NUM> is only present next to an internal surface of the trench structure <NUM> and is made of the same material as the region <NUM>-<NUM>.

<FIG> shows a schematic cross sectional view of the time of flight sensor device <NUM> according to an example not covered by the claims.

The arrangement of the time of flight sensor device <NUM> of <FIG> differs from the arrangement of the time of flight sensor device <NUM> of <FIG> or <FIG> in that the p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM> extends below the trench structure <NUM> in a direction laterally beyond the trench structure <NUM> and further vertically to the first main surface region <NUM>-A of the semiconductor substrate to provide a continuous p-doped region <NUM>-<NUM> of the semiconductor substrate. Thus, the p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM> extends from the main surface region <NUM>-A (from an opposing side of the trench structure <NUM> with respect to the substrate doping region <NUM>) vertically into the semiconductor substrate <NUM> and, below the trench structure <NUM>, laterally to the region of the semiconductor substrate <NUM> vertically below the substrate doping region <NUM>.

Thus, the at least one substrate contact <NUM> may be arranged at the first main surface region <NUM>-A (front side) of the semiconductor substrate <NUM> so that no back side processing of the semiconductor substrate (= wafer) <NUM> is required for providing the at least one substrate contact <NUM> during manufacturing of the optical time of flight sensor device <NUM>.

In some embodiments, the semiconductor substrate <NUM> may only extend below the trench structure(s), i.e. not laterally beyond the later.

<FIG> shows a schematic cross sectional view of the time of flight sensor device <NUM> according to the main embodiment.

As shown in <FIG>, the trench structure <NUM> is buried in the semiconductor substrate <NUM>. To be more specific, the first main surface region <NUM>-A (e.g. top end) of the trench structure <NUM> is offset from the first main surface region <NUM>-A in the depth direction of the semiconductor substrate <NUM>. In the depth direction, the second main surface region <NUM>-B (e.g. bottom end) of the trench structure <NUM> reaches the p-doped region <NUM>-<NUM> of the semiconductor substrate. Thus, the second main surface region <NUM>-b of the trench structure contacts the p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM>.

As shown in <FIG>, a p-doped substrate contact region <NUM> is arranged in the semiconductor substrate <NUM>, this substrate contact region <NUM> having a higher doping concentration than the p-doped region <NUM>-<NUM>. The substrate contact region <NUM> is arranged adjacent to the first main surface region <NUM>-A of the semiconductor substrate <NUM>. The substrate contact region <NUM> may extend at least between the first main surface region <NUM>-A of the semiconductor substrate and the first main surface region <NUM>-A of the buried trench structure <NUM>. Moreover, the upper portion of the substrate doping region <NUM> laterally extends between the substrate contact region <NUM>. Thus, the substrate doping region <NUM> is laterally confined between (the opposing portions of) the substrate contact region <NUM> and the vertically following trench structure <NUM>.

The p-doped substrate contact region <NUM> may comprise a p-type doping concentration in the range between 1E14 atoms/cm<NUM> and 1E20 atoms/cm<NUM>, or between 1E16 atoms/cm<NUM> and 1E19 atoms/cm<NUM>, for example.

The implementation of the time of flight sensor device <NUM> according to embodiment of <FIG> provides more area on the surface <NUM>-A of the semiconductor substrate <NUM> which is available for (optional) active devices (not shown in <FIG>).

<FIG> shows a schematic cross sectional view of the time of flight sensor device according to a further example not covered by the claims.

As shown in <FIG>, the time of flight sensor device <NUM> additionally comprises, as described in reference to the arrangement of <FIG>, a vertical liner <NUM> forming a resistive pinning layer <NUM> in form of a p-doped resistive region of the semiconductor substrate <NUM> which is laterally arranged at least between the substrate doping region <NUM> and the trench structure <NUM>. The resistive pinning layer <NUM> may be arranged between the first main surface region <NUM>-A of the semiconductor substrate <NUM> and the p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM>. Thus, the resistive pinning layer <NUM>, which at least partially or completely laterally surrounds or encloses the substrate doping region <NUM>, may extend from the first main surface region <NUM>-A to the p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM>.

The doping concentration of the pinning layer <NUM> is greater than 1E14 atoms/cm<NUM>, or between 1E14 atoms/cm<NUM> and 1E18 atoms/cm<NUM>, or between 1E15 atoms/cm<NUM> and 1E17 atoms/cm<NUM>, or between 5E15 atoms/cm<NUM> and 5E16 atoms/cm<NUM>, for example and, thus, it is higher than the doping concentration of the p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM>.

Based on the pinning layer <NUM>, the leakage (shot noise) from electron/hole pair generation, at the interface (e.g., SI/SIO2 interface) between the semiconductor material of the semiconductor substrate <NUM> and the isolating (e.g., dielectric) material of the trench structure <NUM> may be suppressed or at least reduced.

One notes that the embodiment of <FIG> may be seen as an embodiment of <FIG> in which the liner <NUM> extends into the region <NUM>-<NUM> and is made of a different material relative to the latter, and is only present next to the internal face of the trench structure <NUM>.

<FIG> shows a schematic cross sectional view of the time of flight sensor device <NUM> according to an alternative embodiment.

The time of flight sensor device as shown in <FIG> may be implemented as described with respect to <FIG>, so that the above description with respect to <FIG> is equally applicable to the embodiment as described below.

As shown in <FIG>, the time of flight sensor device <NUM> comprises the trench structure <NUM> (as described with respect to <FIG>) which is buried in the semiconductor substrate <NUM>. To be more specific, the first main surface region <NUM>-<NUM> of the trench structure <NUM> is offset from the first main surface region <NUM>-A in the depth direction of the semiconductor substrate <NUM>. In the depth direction, the second main surface region <NUM>-B of the trench structure <NUM> reaches the p-doped region <NUM>-<NUM> of the semiconductor substrate. Thus, the second main surface region <NUM>-B of the trench structure contacts the p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM>. As further shown in <FIG>, the p-doped substrate contact region <NUM> is arranged in the semiconductor substrate <NUM> adjacent to the first main surface region <NUM>-A. The substrate contact region <NUM> extends between the first main surface region <NUM>-A of the semiconductor substrate and the first main surface region <NUM>-A of the buried trench structure <NUM>.

As shown in <FIG>, the time of flight sensor device <NUM> further comprises the pinning layer <NUM> (as described with respect e.g. to <FIG>) in form of a p-doped resistive region of the semiconductor substrate <NUM> which is laterally arranged at least between the substrate doping region <NUM> and the trench structure <NUM>.

As shown in <FIG>, the time of flight sensor device <NUM> further comprises the buried doping later <NUM> (as described with respect to <FIG>) which is arranged in the semiconductor substrate vertically (in the z-direction) below the substrate doping region <NUM> and the p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM>. The buried doping layer <NUM> may, for example, extend to the second main surface region <NUM>-B of the semiconductor substrate <NUM>. The buried doping layer <NUM> may be a part of the p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM>. The buried doping layer <NUM> has a higher p-type doping concentration than the p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM> adjacent to the substrate doping region <NUM>.

According to a further embodiment (not shown in <FIG>) the buried doping layer <NUM> may be arranged in the semiconductor substrate <NUM> in the z-direction directly adjacent to the substrate doping region <NUM> in the semiconductor substrate <NUM>. Thus, the buried doping layer <NUM> may form the p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM>.

As shown in <FIG>, the time of flight sensor device <NUM> further comprises the sensor electrode <NUM>, e.g. a so-called separation gate or photogate (modulation gate), (as described with respect to <FIG>) which is optionally separated by an isolating material <NUM> form the semiconductor substrate <NUM> and may be arranged on the first main surface region <NUM>-A of the semiconductor substrate <NUM>. As shown in <FIG>, the sensor electrode <NUM> may be arranged in a lateral direction between the control electrode <NUM> and the readout node <NUM>. Moreover, the further sensor electrode <NUM>-<NUM> may be optionally provided on the first main surface region <NUM>-A of the semiconductor substrate <NUM> in combination with the further control electrode <NUM>-<NUM>. Moreover, the further sensor electrode(s) <NUM>-<NUM>,. , may be provided on the first main surface region <NUM>-A of the semiconductor substrate <NUM> for redirecting the photo-generated charge carriers to respective readout node <NUM>, <NUM>-<NUM>.

Based on the implementation of the time of flight sensor device <NUM> according <FIG>, a very efficient demodulation of the photo-generated charge carriers in the conversion region <NUM> is achieved.

As shown in <FIG> (when compared to the implementation of <FIG>), the trench material filling the trench structure <NUM> comprises charges <NUM> (negative charge carriers or negatively charged regions) neighboring the lateral main surface region <NUM>-C of the trench structure <NUM>. The dielectric trench filling material may comprise, for example, AL<NUM><NUM><NUM>, wherein the AL<NUM>O<NUM> material may comprise a layer-like structure. The negative charge carriers <NUM> may attract positive charge carries (holes) <NUM> from the substrate material of the semiconductor substrate <NUM> at the lateral region <NUM>-A of the substrate doping region <NUM>. More precisely, negative charges <NUM> are stored in the dielectric material of the trench structure <NUM> which leads to an accumulation of holes <NUM> at the lateral region <NUM>-A of the substrate doping region <NUM> bordering to the trench structure <NUM>.

The accumulation of holes <NUM> at the lateral region <NUM>-A of the substrate doping region <NUM> influences the electrical equipotential lines in the substrate doping region <NUM> which results in a more efficient demodulation of the photo-generated charge carriers 114b. Furthermore, the leakage (shot noise) from an electron/hole pair generation at the interface between the semiconductor material of the semiconductor substrate <NUM> and the dielectric material of the trench structure <NUM> may be suppressed or at least reduced. These results are achievable with a minimum space requirement based on the implementation of the time of flight sensor device <NUM> according to the embodiment of <FIG>.

The arrangement of the time of flight sensor device <NUM> of <FIG> differs from the arrangement of the time of flight sensor device <NUM> of <FIG> in that, instead of the pinning layer <NUM>, the trench material filling the trench structure <NUM> comprises charges <NUM> (negative charge carriers or negatively charged regions) neighboring to the lateral main surface region <NUM>-C of the trench structure <NUM>.

As shown in <FIG>, the time of flight sensor device <NUM> comprises the trench structure <NUM> which is buried in the semiconductor substrate <NUM>.

The time of flight sensor device <NUM> further comprises the buried doping later <NUM> which is arranged in the semiconductor substrate vertically (in the z-direction) below the substrate doping region <NUM> and the p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM>.

Moreover, the at least one additional sensor electrode(s) <NUM>, <NUM>-<NUM>, <NUM>-<NUM>,. , e.g. a so-called separation gate or photogate (modulation gate), may be provided on the first main surface region <NUM>-A of the semiconductor substrate <NUM> for redirecting the photo-generated charge carriers to respective readout node <NUM>, <NUM>-<NUM>.

According to another embodiment, a time of flight sensor device <NUM> comprises a semiconductor substrate <NUM>. The semiconductor substrate <NUM> comprises a conversion region <NUM> to convert an electromagnetic signal S<NUM> in photo-generated charge carriers 114a, 114b. The semiconductor substrate <NUM> further comprises a substrate doping region <NUM> having a n doping type, wherein the substrate doping region <NUM> extends from a first main surface region <NUM>-A of the semiconductor substrate <NUM> into the semiconductor substrate <NUM> (in the depth direction or z direction).

The semiconductor substrate <NUM> has adjacent to the substrate doping region <NUM> a p-doped region <NUM>-<NUM>, i.e. the remaining region <NUM>-<NUM> of the semiconductor substrate <NUM>-<NUM> adjacent to the substrate doping region <NUM> has a p-doping type. The substrate doping region <NUM> at least partially forms the conversion region <NUM> in the semiconductor substrate. A readout node <NUM> is arranged in the semiconductor substrate <NUM> within the substrate doping region <NUM> and has the n doping type e.g. with a higher doping concentration than the substrate doping region <NUM>. The readout node <NUM> is configured to readout the photo generated charge carriers 114b, e.g., the photo-generated electrons.

A control electrode <NUM> is arranged in or on the substrate doping region of the semiconductor substrate. A buried doping layer <NUM> in the semiconductor substrate having a higher concentration of the p doping type than p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM> is arranged adjacent to the substrate doping region <NUM>, wherein the buried doping layer <NUM> is formed in the semiconductor substrate <NUM> and vertically below the substrate doping region <NUM> in the semiconductor substrate <NUM>.

As exemplarily shown in <FIG>, the control electrode(s) <NUM>, <NUM>-<NUM> of the time of flight sensor device <NUM> may be arranged on the substrate doping region <NUM> of the semiconductor substrate <NUM> and may be separated by an insulating material <NUM> from the semiconductor substrate <NUM>, e.g. in form of a metallization or polysilicon region <NUM>, <NUM>-<NUM> with an intermediate insulator layer <NUM> on the main surface region <NUM>-A of the semiconductor substrate <NUM>.

Alternatively, the control electrode(s) <NUM>, <NUM>-<NUM> may arranged in the substrate doping region <NUM> of the semiconductor substrate <NUM> and may have the p doping type, e.g. as an implanted p doping region in the semiconductor substrate <NUM>. Thus, the control electrode(s) <NUM>, <NUM>-<NUM> may correspond to the control electrode(s) <NUM>, <NUM>-<NUM> of the time of flight sensor device <NUM> (e.g. as described with respect to <FIG> and <FIG>).

According to an embodiment, the buried doping layer <NUM> of the time of flight sensor device <NUM> of <FIG> structurally and functionally corresponds to the buried doping layer <NUM> of the time of flight sensor device <NUM> of <FIG>, wherein the doping concentration of the buried doping layer <NUM> of <FIG> is exemplarily shown in <FIG> as a schematic plot having the two exemplary alternatives I, II of the doping profile D<NUM> of the buried semiconductor layer <NUM> in the depth direction (= z-direction) of the semiconductor substrate <NUM>. Thus, the above description of the structure and functionality of the buried doping layer <NUM> of the time of flight sensor device <NUM> (e.g. with respect to <FIG>) is equally applicable to the embodiment of the time of flight sensor device <NUM> as described with respect to <FIG>.

According to a further embodiment, the time of flight sensor device <NUM> may comprise a trench structure (not shown in <FIG>) which is arranged laterally with respect to the substrate doping region <NUM> and extends vertically with respect to the first main surface region <NUM>-A of the semiconductor substrate <NUM> into the semiconductor substrate <NUM>. Thus, the above description of the structure and functionality of the trench structure <NUM> of the time of flight sensor device <NUM> (e.g. with respect to <FIG>) is equally applicable to the embodiment of the time of flight sensor device <NUM> as described with respect to <FIG>.

The optional further control electrode <NUM>-<NUM> may be also arranged in or on the substrate doping region <NUM> of the semiconductor substrate <NUM>. As shown in <FIG>, the further control electrode <NUM>-<NUM> may also be arranged in the conversion region <NUM> adjacent to the first main surface region <NUM>-A of the semiconductor substrate <NUM>. The further control electrode <NUM>-<NUM> may be formed as implanted doping region in the semiconductor substrate <NUM>. The further control electrode <NUM>-<NUM> may comprise the same p-type doping concentration as the control electrode <NUM>, for example.

Alternatively, the further control electrode <NUM>-<NUM> may be arranged on the substrate doping region <NUM> of the semiconductor substrate <NUM> and is separated by an insulating material <NUM> from the semiconductor substrate, e.g. in form of a metallization or polysilicon region <NUM>-<NUM> with an intermediate insulator layer <NUM> on the main surface region <NUM>-A of the semiconductor substrate <NUM>.

Thus, the above description of the structure and functionality of the further readout node <NUM>-<NUM> and the further control electrode <NUM>-<NUM> of the time of flight sensor device <NUM> (e.g. with respect to <FIG>) is equally applicable to the embodiment of the time of flight sensor device <NUM> as described with respect to <FIG>.

As shown in <FIG>, a further substrate contact <NUM>-<NUM> may be optionally provided at the p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM>. In case, the further substrate contact <NUM>-<NUM> is arranged, the above description of the structure and functionality of the substrate contact <NUM>-<NUM> of the time of flight sensor device <NUM> is equally applicable to the further substrate contact <NUM>-<NUM> of the time of flight sensor device <NUM>.

<FIG> show schematic cross sectional views of the time of flight sensor device according to further embodiments.

The time of flight sensor device <NUM> as shown in <FIG> may be implemented as described with respect to <FIG> wherein the time of flight sensor device <NUM> may further comprise a trench structure <NUM> in the semiconductor substrate <NUM> which is arranged laterally with respect to the substrate doping region <NUM> and extends vertically with respect to the first main surface region <NUM>-A of the semiconductor substrate <NUM> into the semiconductor substrate <NUM>. The trench structure <NUM> may be buried in the semiconductor substrate <NUM> Thus, the above description of the structure and functionality of the trench structure <NUM> of the time of flight sensor device <NUM> (e.g. with respect to <FIG>) is equally applicable to the embodiment of the time of flight sensor device <NUM> as described with respect to <FIG>.

As exemplarily shown in <FIG>, the control electrode(s) <NUM>, <NUM>-<NUM> of the time of flight sensor device <NUM> may be arranged on the substrate doping region <NUM> of the semiconductor substrate <NUM> and may be separated by an insulating material <NUM> from the semiconductor substrate, e.g. in form of a metallization or polysilicon region <NUM>, <NUM>-<NUM> with an intermediate insulator layer <NUM> on the main surface region <NUM>-A of the semiconductor substrate <NUM>. Alternatively, the control electrode(s) <NUM> may arranged in the substrate doping region <NUM> of the semiconductor substrate <NUM> and may have the p doping type, e.g. as an implanted p doping region in the semiconductor substrate <NUM>. Thus, the control electrode(s) <NUM>, <NUM>-<NUM> of the time of flight sensor device <NUM> may correspond to the control electrode(s) <NUM>, <NUM>-<NUM> of the time of flight sensor device <NUM> (e.g. as described with respect to <FIG> and <FIG>).

As shown in <FIG>, the trench structure <NUM> is buried in the semiconductor substrate <NUM>, wherein the p-doped substrate contact region <NUM> is arranged in the semiconductor substrate <NUM> adjacent to the first main surface region <NUM>-A of the semiconductor substrate <NUM> and extends at least between the first main surface region <NUM>-A of the semiconductor substrate and the first main surface region <NUM>-A of the buried trench structure <NUM>. The second main surface region <NUM>-b of the trench structure contacts the p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM>.

As shown in <FIG>, the time of flight sensor device <NUM> may further comprise the pinning layer <NUM> in form of a p-doped resistive region of the semiconductor substrate <NUM> which is laterally arranged between the substrate doping region <NUM> and the trench structure <NUM>. The time of flight sensor device <NUM> may further comprise the buried doping later <NUM> which is arranged in the semiconductor substrate vertically below the substrate doping region <NUM> of the semiconductor substrate <NUM>. The buried doping layer <NUM> may be a part of the p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM>. The buried doping layer <NUM> has a higher p-type doping concentration than the p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM> adjacent to the substrate doping region <NUM>.

<FIG> shows a schematic cross sectional view of the time of flight sensor device <NUM> according to a further embodiment. The arrangement of the time of flight sensor device <NUM> of <FIG> differs from the arrangement of the time of flight sensor device <NUM> of <FIG> in that, instead of the pinning layer <NUM>, the trench material filling the trench structure <NUM> comprises charges <NUM> (negative charge carriers or negatively charged regions) neighboring to the lateral main surface region <NUM>-C of the trench structure <NUM>. Thus, the above description of the structure and functionality of the trench structure <NUM> of the time of flight sensor device <NUM> (e.g. with respect to <FIG>) is equally applicable to the embodiment of the time of flight sensor device <NUM> as described with respect to <FIG>.

As shown in <FIG>, the time of flight sensor device <NUM> comprises the trench structure <NUM> which is buried in the semiconductor substrate <NUM>. The time of flight sensor device <NUM> further comprises the buried doping later <NUM> which is arranged in the semiconductor substrate vertically (in the z-direction) below the substrate doping region <NUM> and the p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM>.

As exemplarily shown in <FIG>, the control electrode(s) <NUM>, <NUM>-<NUM> of the time of flight sensor device <NUM> may be arranged on the substrate doping region <NUM> of the semiconductor substrate <NUM> and may be separated by an insulating material <NUM> from the semiconductor substrate, e.g. in form of a metallization or polysilicon region <NUM>, <NUM>-<NUM> with an intermediate insulator layer <NUM> on the main surface region <NUM>-A of the semiconductor substrate <NUM>. Alternatively, the control electrode(s) <NUM>, <NUM>-<NUM> may arranged in the substrate doping region <NUM> of the semiconductor substrate <NUM> and may have the p doping type, e.g. as an implanted p doping region in the semiconductor substrate <NUM>. Thus, the control electrode(s) <NUM>, <NUM>-<NUM> may correspond to the control electrode(s) <NUM>, <NUM>-<NUM> of the time of flight sensor device <NUM> (e.g. as described with respect to <FIG> and <FIG>).

<FIG> shows a schematic cross sectional view of a time of flight sensor device <NUM> according to further embodiments.

According to another embodiment, the time of flight sensor device <NUM> comprises a semiconductor substrate <NUM>. The semiconductor substrate <NUM> comprises a conversion region <NUM> to convert an electromagnetic signal S<NUM> in photo-generated charge carriers 114a, 114b. The semiconductor substrate <NUM> further comprises a substrate doping region <NUM> having a n doping type, wherein the substrate doping region <NUM> extends from a first main surface region <NUM>-A of the semiconductor substrate <NUM> into the semiconductor substrate <NUM> (in the depth direction or z direction).

The semiconductor substrate <NUM> has adjacent to the substrate doping region <NUM> a p-doped region <NUM>-<NUM>, i.e. the remaining region <NUM>-<NUM> of the semiconductor substrate <NUM>-<NUM> adjacent to the substrate doping region <NUM> has a p-doping type. The substrate doping region <NUM> at least partially forms the conversion region <NUM> in the semiconductor substrate.

A readout node <NUM> is arranged in the semiconductor substrate <NUM> within the substrate doping region <NUM> and has the n doping type e.g. with a higher doping concentration than the substrate doping region <NUM>. The readout node <NUM> is configured to readout the photo generated charge carriers 114b, e.g., the photo-generated electrons.

A control electrode <NUM> is arranged in or on the substrate doping region of the semiconductor substrate.

The time of flight sensor device <NUM> further comprises a trench structure <NUM> in the semiconductor substrate <NUM> which is arranged laterally with respect to the substrate doping region <NUM> and extends vertically with respect to the first main surface region <NUM>-A of the semiconductor substrate <NUM> into the semiconductor substrate <NUM>.

Thus, the above description of the different implementations of the time of flight sensor device <NUM> regarding the structure and functionality of the trench structure <NUM> (e.g. with respect to <FIG>) is equally applicable to the time of flight sensor device <NUM> as described with respect to <FIG>.

As exemplarily shown in <FIG>, the control electrode(s) <NUM>, <NUM>-<NUM> of the time of flight sensor device <NUM> may be arranged on the substrate doping region <NUM> of the semiconductor substrate <NUM> and may be separated by an insulating material <NUM> from the semiconductor substrate, e.g. in form of a metallization or polysilicon region <NUM>, <NUM>-<NUM> with an intermediate insulator layer <NUM> on the main surface region <NUM>-A of the semiconductor substrate <NUM>.

Alternatively, the control electrode(s) <NUM>, <NUM>-<NUM> may arranged in the substrate doping region <NUM> of the semiconductor substrate <NUM> and may have the p doping type, e.g. as an implanted p doping region in the semiconductor substrate <NUM>. Thus, the control electrode(s) <NUM>, <NUM>-<NUM> of the time of flight sensor device <NUM> may correspond to the control electrode(s) <NUM>, <NUM>-<NUM> of the time of flight sensor device <NUM> (e.g. as described with respect to <FIG> and <FIG>).

According to a further embodiment, the trench structure <NUM> may be laterally spaced from the substrate doping region <NUM>, wherein at least a part of the p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM> is arranged between the substrate doping region <NUM>-<NUM> and the trench structure <NUM> (see also <FIG> and the associated description, for example).

According to a further embodiment, the trench structure <NUM> may be arranged directly adjacent to the substrate doping region <NUM> (see also <FIG> and the associated description, for example).

According to a further embodiment, the time of flight sensor device <NUM> may further optionally comprise a trench pinning layer <NUM> (not shown in <FIG>) in form of a p doped resistive region of the semiconductor substrate <NUM>, wherein the trench pinning layer <NUM> is arranged adjacent to the trench structure <NUM> and at least between the trench structure <NUM> and the substrate doping region <NUM> and extends to the p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM> (see also <FIG> and the associated description, for example).

According to a further embodiment, a further doping region (= pinning layer) <NUM> having a p-doping type may be optionally arranged between the control electrodes <NUM>, <NUM>-<NUM> in the substrate doping region <NUM> adjacent to the first main surface region <NUM>-A of the semiconductor substrate <NUM> (see also <FIG> and the associated description, for example).

According to a further embodiment, the trench structure <NUM> comprises a trench dielectric material with stored charge carriers <NUM> in the trench dielectric material adjacent to the substrate doping region <NUM> (see also <FIG> and the associated description, for example).

According to a further embodiment, the trench structure <NUM> may be buried in the semiconductor substrate <NUM> and extends in the p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM> (see also <FIG>, <FIG>, <FIG> and the associated description, for example).

According to a further embodiment, the time of flight sensor device <NUM> may further comprise a substrate contact region <NUM> having the p doping type in the semiconductor substrate <NUM> and adjacent to the first main surface region <NUM> of the semiconductor substrate <NUM> (see also <FIG>, <FIG>, <FIG> and the associated description, for example).

According to an embodiment, the substrate contact region <NUM> is arranged between the first main surface region <NUM>-A of the semiconductor substrate <NUM> and the buried trench structure <NUM> (see also <FIG>, <FIG>, <FIG> and the associated description, for example).

According to a further embodiment, the trench structure <NUM> extends between the substrate contact region <NUM> and a buried doping layer <NUM> (see also <FIG>, <FIG> and the associated description, for example). The buried doping layer <NUM> in the semiconductor substrate having a higher concentration of the p doping type than p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM> may be arranged adjacent to the substrate doping region <NUM>, wherein the buried doping layer <NUM> is formed in the semiconductor substrate <NUM> and vertically below the substrate doping region <NUM> in the semiconductor substrate <NUM>. Thus, the above description of the structure and functionality of the buried doping layer <NUM> of the time of flight sensor device <NUM> (e.g. with respect to <FIG>) is equally applicable to the embodiment of the time of flight sensor device <NUM> as described with respect to <FIG>.

<FIG> shows an exemplary schematic circuit diagram of a time of flight sensor arrangement according to a further embodiment.

According to another embodiment, a time of flight sensor arrangement <NUM> comprises: a plurality of pixels respectively having one of time of flight sensor devices <NUM>, <NUM>, <NUM>, wherein the pixels are arranged in an array <NUM> (e.g. a n x m array, with n ≥ <NUM> (<NUM>, <NUM>, <NUM>, <NUM>,. ) and m ≥ <NUM> (<NUM>, <NUM>, <NUM>, <NUM>,. ), and a controller <NUM> for providing a control signal Cxm to the respective control electrode(s) <NUM>, <NUM>-<NUM>.

The optical time of flight sensor device <NUM> may be configured to detect a time of flight of the electromagnetic signal S<NUM>, S<NUM>, which enters the conversion region <NUM>. To this end, the optical time of flight sensor device <NUM> may further comprise a controller which may be configured to apply a varying potential to the control electrode(s) <NUM>, <NUM>-<NUM>, to generate electrical potential distributions in the substrate doping region <NUM> and the conversion region <NUM>, by which, the photo-generated charge carriers in the conversion region <NUM> are directed in different directions, e.g. towards the read-out region(s) <NUM>, <NUM>-<NUM>, dependent on the time of flight of the electromagnetic signal S<NUM>, S<NUM>, which enters the conversion region.

The varying potential, applied by the controller to the control electrode(s) is a demodulation signal having a fixed phase relationship with a modulation signal with which the electromagnetic signal S<NUM> is modulated.

The controller <NUM> may be further configured to determine the time of flight of the electromagnetic signal S<NUM>, S<NUM> based on a relationship of the amount of charge carriers collected at the first readout node <NUM> and/or the amount of charge carriers collected at the second readout node <NUM>-<NUM>. In embodiments, the controller <NUM> may be formed of any appropriate integrated circuit and may be integrated with the optical time of flight sensor device <NUM>. In embodiments, the controller may be provided by an integrated circuit separate from the semiconductor substrate of the optical sensor device. In embodiments, at least parts of the controller may be formed by a microprocessor or an FPGA (Field Programmable Gate Array) or an ASIC (Application-Specific Integrated Circuit).

Additional embodiments and aspects are described which may be used alone or in combination with the features and functionalities described herein.

According to an embodiment, a time of flight sensor device <NUM> comprises: a semiconductor substrate <NUM> comprising a conversion region <NUM> to convert an electromagnetic signal S in photo-generated charge carriers 114a, 114b, and comprising a substrate doping region <NUM> having a n doping type, wherein the substrate doping region <NUM> extends from a first main surface region <NUM>-A of the semiconductor substrate <NUM> into the semiconductor substrate <NUM>, wherein the semiconductor substrate <NUM> has adjacent to the substrate doping region <NUM> a p doped region <NUM>-<NUM>, and wherein the substrate doping region <NUM> at least partially forms the conversion region <NUM> in the semiconductor substrate <NUM>, a readout node <NUM> arranged in the semiconductor substrate <NUM> within the substrate doping region <NUM> and having the n-doping type, wherein the readout node <NUM> is configured to readout the photo generated charge carriers 114b; and a control electrode <NUM> arranged in the substrate doping region <NUM> of the semiconductor substrate <NUM> and in the substrate doping region <NUM> and having the p-doping type.

According to one aspect, the conversion region <NUM> vertically extends beyond the substrate doping region <NUM> in the semiconductor substrate <NUM>.

According to another aspect, the time of flight sensor device <NUM> further comprises: a sensor electrode <NUM> which is separated by an isolating material <NUM> from the semiconductor substrate <NUM>, wherein the sensor electrode <NUM> is configured to modify an electric potential distribution in the substrate doping region <NUM>.

According to another aspect, the time of flight sensor device <NUM> further comprises: a further control electrode <NUM>-<NUM> arranged in the substrate doping region <NUM> of the semiconductor substrate <NUM> and having the p-doping type, and a resistive pinning layer <NUM> in form of a p doped resistive region of the semiconductor substrate <NUM>, wherein the resistive pinning layer <NUM> is arranged in the semiconductor substrate <NUM> adjacent to the first main surface region <NUM>-A and between the two control electrodes <NUM>, <NUM>-<NUM>.

According to another aspect, the time of flight sensor device <NUM> further comprises: a buried doping layer <NUM> in the semiconductor substrate <NUM> having a higher concentration of the p doping type than the p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM> adjacent to the substrate doping region <NUM>, wherein the buried doping layer <NUM> is formed vertically below the substrate doping region <NUM> in the semiconductor substrate <NUM>.

According to another aspect, the buried doping layer <NUM> provides a graded doping profile in the semiconductor substrate <NUM> having a maximum doping concentration of the p doping type in an intermediate region <NUM>-<NUM> of the buried doping layer.

According to another aspect, the time of flight sensor device <NUM> further comprises: a trench structure <NUM> which is arranged laterally with respect to the substrate doping region <NUM> and extends vertically with respect to the first main surface region <NUM>-a of the semiconductor substrate <NUM> in the semiconductor substrate <NUM>.

According to another aspect, the trench structure <NUM> is arranged directly adjacent to the substrate doping region <NUM>.

According to another aspect, the trench structure <NUM> is laterally spaced from the substrate doping region <NUM>, wherein at least a part of the p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM> is arranged between the substrate doping region <NUM> and the trench structure <NUM>.

According to another aspect, the time of flight sensor device <NUM> further comprises: a trench pinning layer <NUM> in form of a p doped resistive region of the semiconductor substrate <NUM>, wherein the trench pinning layer <NUM> is arranged adjacent to the trench structure <NUM> and is arranged at least between the trench structure <NUM> and the substrate doping region <NUM> and extends to the p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM>.

According to another aspect, the trench structure <NUM> comprises a trench dielectric material with stored charge carriers in the trench dielectric material adjacent to the substrate doping region <NUM>.

According to another aspect, the trench structure <NUM> is buried in the semiconductor substrate <NUM> and reaches in the depth direction the p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM>.

According to another aspect, the time of flight sensor device <NUM> further comprises: a substrate contact region <NUM> having the p doping type in the semiconductor substrate <NUM> and adjacent to the first main surface region <NUM>-A of the semiconductor substrate <NUM>.

According to another aspect, the substrate contact region <NUM> is arranged between the first main surface region <NUM>-A of the semiconductor substrate <NUM> and the trench structure <NUM>.

According to another aspect, the buried trench structure <NUM> extends between the substrate contact region <NUM> and the buried doping layer <NUM>.

According to another embodiment, a time of flight sensor device <NUM> comprises: a semiconductor substrate comprising a conversion region to convert an electromagnetic signal in photo-generated charge carriers, and comprising a substrate doping region having a n doping type, wherein the substrate doping region extends from a first main surface region of the semiconductor substrate into the semiconductor substrate, wherein the semiconductor substrate has adjacent to the substrate doping region a p-doped region <NUM>-<NUM>, and wherein the substrate doping region at least partially forms the conversion region in the semiconductor substrate, a readout node arranged in the semiconductor substrate within the substrate doping region and having the n doping type, wherein the readout node is configured to readout the photo generated charge carriers, a control electrode arranged in or on the substrate doping region of the semiconductor substrate, and a buried doping layer <NUM> in the semiconductor substrate having a higher concentration of the p doping type than p-doped region of the semiconductor substrate adjacent to the substrate doping region, wherein the buried doping layer is formed in the semiconductor substrate and vertically below the substrate doping region <NUM> in the semiconductor substrate <NUM>.

According to one aspect, the control electrode is arranged in in the substrate doping region and having the p doping type, or the control electrode is arranged on the substrate doping region of the semiconductor substrate and is separated by an isolating material from the semiconductor substrate.

According to another aspect, the buried doping layer provides a graded doping profile in the semiconductor substrate having a maximum doping concentration of the p doping type in an intermediate region of the buried doping layer.

According to another aspect, the time of flight sensor device further comprises: a trench structure which is arranged laterally with respect to the substrate doping region and extends vertically with respect to the first main surface region of the semiconductor substrate in the semiconductor substrate.

According to another embodiment, a time of flight sensor device <NUM> comprises: a semiconductor substrate comprising a conversion region to convert an electromagnetic signal in photo-generated charge carriers, and comprising a substrate doping region having a n doping type, wherein the substrate doping region extends from a first main surface region of the semiconductor substrate into the semiconductor substrate, wherein the semiconductor substrate <NUM> has adjacent to the substrate doping region <NUM> a p-doped region <NUM>-<NUM>, and wherein the substrate doping region at least partially forms the conversion region in the semiconductor substrate, a readout node arranged in the semiconductor substrate within the substrate doping region and having the n doping type, wherein the readout node is configured to readout the photo generated charge carriers; a control electrode arranged in or on the substrate doping region of the semiconductor substrate, and a trench structure which is arranged laterally with respect to the substrate doping region and which extends vertically with respect to the first main surface region of the semiconductor substrate in the semiconductor substrate.

According to one aspect, the control electrode is arranged in the substrate doping region and having the p doping type, or wherein the control electrode is arranged on the substrate doping region of the semiconductor substrate and is separated by an isolating material from the semiconductor substrate.

According to another aspect, the trench structure is arranged directly adjacent to the substrate doping region.

According to another aspect, the trench structure is laterally spaced from the substrate doping region, wherein the p-doped region <NUM>-<NUM> of the semiconductor substrate <NUM> is arranged between the substrate doping region and the trench structure.

According to another aspect, the time of flight sensor device <NUM> further comprises: a trench pinning layer in form of a p doped resistive region of the semiconductor substrate, wherein the trench pinning layer is arranged adjacent to the trench structure and at least between the trench structure and the substrate doping region and extends to the p-doped region <NUM>-<NUM> of the semiconductor substrate.

According to another aspect, the trench structure comprises a trench dielectric material with stored charge carriers in the trench dielectric material adjacent to the substrate doping region.

According to another aspect, the trench structure is buried in the semiconductor substrate and extends in the p-doped region <NUM>-<NUM> of the semiconductor substrate.

According to another aspect, the time of flight sensor device <NUM> further comprises: a substrate contact region having the p doping type in the semiconductor substrate and adjacent to the first main surface region of the semiconductor substrate.

According to another aspect, the substrate contact region is arranged between the first main surface region of the semiconductor substrate and the trench structure.

According to another aspect, the trench structure extends between the substrate contact region and the buried doping layer <NUM>.

According to another embodiment, a time of flight sensor arrangement <NUM> comprises: a plurality of the time of flight sensor devices <NUM>, <NUM>, <NUM>, wherein the time of flight sensor devices <NUM>, <NUM>, <NUM> are arranged in an array, and a controller for providing a control signal to the control electrode.

Although some aspects have been described as features in the context of an apparatus it is clear that such a description may also be regarded as a description of corresponding features of a method. Although some aspects have been described as features in the context of a method, it is clear that such a description may also be regarded as a description of corresponding features concerning the functionality of an apparatus.

In the foregoing Detailed Description, it can be seen that various features are grouped together in examples for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed examples require more features than are expressly recited in each claim. Rather, as the following claims reflect, subject matter may lie in less than all features of a single disclosed example. Thus the following claims are hereby incorporated into the Detailed Description, where each claim may stand on its own as a separate example. While each claim may stand on its own as a separate example, it is to be noted that, although a dependent claim may refer in the claims to a specific combination with one or more other claims, other examples may also include a combination of the dependent claim with the subject matter of each other dependent claim or a combination of each feature with other dependent or independent claims. Such combinations are proposed herein unless it is stated that a specific combination is not intended.

Claim 1:
A time of flight sensor device (<NUM>), comprising:
a semiconductor substrate (<NUM>) comprising a conversion region (<NUM>) to convert an electromagnetic signal (S) in photo-generated charge carriers (114a, 114b), and comprising a substrate doping region (<NUM>) having a n doping type,
wherein the substrate doping region (<NUM>) extends from a first main surface region (<NUM>-A) of the semiconductor substrate (<NUM>) into the semiconductor substrate (<NUM>),
wherein the semiconductor substrate (<NUM>) has adjacent to the substrate doping region (<NUM>) a p doped region (<NUM>-<NUM>), and
wherein the substrate doping region (<NUM>) at least partially forms the conversion region (<NUM>) in the semiconductor substrate (<NUM>),
a readout node (<NUM>) arranged in the semiconductor substrate (<NUM>) within the substrate doping region (<NUM>) and having the n-doping type, wherein the readout node (<NUM>) is configured to readout the photo generated charge carriers (114b);
a control electrode (<NUM>) arranged in the substrate doping region (<NUM>) and having the p-doping type;
a trench structure (<NUM>) which is arranged laterally with respect to the substrate doping region (<NUM>) and extends vertically with respect to the first main surface region (<NUM>-a) of the semiconductor substrate (<NUM>) in the semiconductor substrate (<NUM>); and
a substrate contact region (<NUM>) having the p doping type in the semiconductor substrate (<NUM>) and adjacent to the first main surface region (<NUM>-A) of the semiconductor substrate (<NUM>);
wherein the substrate contact region (<NUM>) is arranged between the first main surface region (<NUM>-A) of the semiconductor substrate (<NUM>) and a first main surface region (<NUM>-A) of the trench structure (<NUM>), and wherein the first main surface region (<NUM>-A) of the trench structure (<NUM>) forms a top end of the trench structure (<NUM>) and is offset from the first main surface region (<NUM>-A) in the depth direction of the semiconductor substrate (<NUM>).