Abstract:
A semiconductor component has at least one Peltier element and at least one thermogenerator element that are thermally coupled to one another via a coupling device. By virtue of the thermal coupling of the Peltier element and the thermogenerator element through the coupling device, it is possible to use the Peltier element to cool a microstructure, in particular an optoelectronic component (e.g. a laser diode). Efficient temperature regulation and efficient operation of an optoelectronic component are thus possible.

Description:
BACKGROUND OF THE INVENTION 
   Field of the Invention 
   The invention relates to a semiconductor component having at least one microstructure being an optoelectronic component. 
   Optoelectronic communications technology nowadays makes use of microstructures, such as e.g. laser diodes, which have a considerable cooling requirement and require an integrated circuit as a controller device. Other active or passive electronic components or else microstructures from the field of biotechnology (e.g. biochips) also frequently need to be cooled. 
   Such microstructures can be cooled by convection or thermal conduction. In the case of convective cooling, a gas stream is brought into contact with the microstructure to be cooled. In the case of cooling by thermal conduction, a heat sink is connected to the microstructure to be cooled. Such a heat sink may contain e.g. a Peltier element known per se. 
   Published, Non-Prosecuted German Patent Application DE 198 45 104 A discloses a thermoelectric transducer produced in a sandwich configuration. The transducer has a series of thermoelement cells, which are connected in series by a common interconnect. Such a transducer can also be used as a heat sink for optoelectronic components. 
   In optoelectronics and in other fields, the microstructures are becoming smaller, so that a higher integration density, in particular also for cooling elements and controller devices, is desirable. 
   SUMMARY OF THE INVENTION 
   It is accordingly an object of the invention to provide a semiconductor component that overcomes the above-mentioned disadvantages of the prior art devices of this general type, with which temperature regulation and also an operation of a microstructure, in particular of an optoelectronic component, are possible in an efficient manner. 
   With the foregoing and other objects in view there is provided, in accordance with the invention, a semiconductor component. The semiconductor component contains at least one microstructure, at least one Peltier element for cooling the microstructure, at least one thermogenerator element, and a coupling device thermally coupling the Peltier element and the thermogenerator element to one another. The coupling device additionally supports the microstructure. 
   By virtue of the thermal coupling of the Peltier element and the thermogenerator element via the coupling device, it is possible by use of the Peltier element to cool a microstructure, in particular an optoelectronic component (e.g. a laser diode), but at the same time to use a temperature difference that arises by the thermogenerator element for voltage generation purposes. It is thus possible to achieve, in particular, a compact configuration of the entire component with a temperature regulating device. 
   In an advantageous manner, the coupling device has a semiconductor layer, in particular a silicon semiconductor layer, or contains silicon. Silicon has a high thermal conductivity, silicon also being suitable, in particular, for the construction of semiconductor structures. 
   In an advantageous manner, the Peltier element and/or the thermogenerator element are constructed as a thermoelectric transducer in a sandwich configuration. Such a transducer is disclosed e.g. in DE 198 45 104 A1 and will also be described later. In this case, it is particularly advantageous if the thermoelectric transducer in a sandwich configuration has a plurality of series-connected thermoelement cells, which are connected to one another in series by a plurality of electrical interconnects. Each thermoelement cell has a first body made of a first thermoelectric material of a first conductivity type and a second body made of a second thermoelectric material of a second conductivity type, which are connected to one another by a second electrical interconnect and which are disposed in a sandwich-like manner between a first substrate wafer and a second electrically insulating substrate wafer. Alternatively, a second substrate wafer has an insulating layer, the first substrate wafer and the second substrate wafer are connected to one another in such a way that the first and second interconnects and the first and second bodies are disposed between the two substrate wafers and form a plurality of series-connected thermoelement cells. A transducer can be realized as a semiconductor sandwich construction, which permits particularly miniaturized structural forms. Such a sandwich structure can be produced in a simple manner by photomask and etching techniques. 
   The semiconductor component according to the invention can advantageously be used in conjunction with a laser component coupled to the coupling device, in particular a laser diode or a laser-based gas sensor. 
   Furthermore, it is advantageous if provision is made for at least one integrated circuit and/or a thermistor for controlling at least one laser diode. 
   In this case, it is advantageous if the laser diode, the integrated circuit and/or the thermistor are coupled to the coupling device in a hybrid design. 
   It is also advantageous if the laser diode, the integrated circuit and/or the thermistor are coupled to the coupling device in a monolithic integrated design. 
   The energy requirement of the optoelectronic components is lowered if at least one thermogenerator element is part of the voltage supply for an integrated circuit. 
   In an advantageous manner, at least one microstructure is formed as an active electronic component, a passive electronic component, as a microreactor, or as a cavity for receiving a liquid, in particular in the context of a DNA analysis and/or DNA synthesis. The microstructures also need temperature control during operation, and this can be achieved in an efficient manner by the semiconductor component according to the invention. 
   It is also advantageous if a microstructure whose temperature is to be regulated has a receptacle device for the cultivation of cells, in particular yeasts, human cells or bacteria. 
   In a further advantageous refinement, at least one microstructure whose temperature is to be regulated is formed as a gas chromatograph capillary disposed in the coupling device. 
   In an advantageous manner, the semiconductor component according to the invention has a device for smoothing the current generated by the thermogenerator element. It is particularly advantageous, since it saves space, if the device for smoothing the current is disposed in an integrated circuit of the semiconductor component. 
   It is also advantageous if at least one thermogenerator element can be used as a measurement sensor for temperature regulation. 
   Other features which are considered as characteristic for the invention are set forth in the appended claims. 
   Although the invention is illustrated and described herein as embodied in a semiconductor component, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. 
   The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a diagrammatic, side-elevational view of a first embodiment of a semiconductor component according to the invention with a hybrid configuration of a laser diode, an integrated circuit, and a thermistor; 
       FIG. 2  is a perspective illustration of the first embodiment according to  FIG. 1 ; 
       FIG. 2   a  is a plan view of a detail of the Peltier element of the first embodiment according to  FIG. 1 ; 
       FIG. 3  is a diagrammatic, side-elevational view of a second embodiment of the semiconductor component according to the invention with a monolithic integrated configuration of the laser diode, the integrated circuit and the thermistor; 
       FIG. 4  is a perspective illustration of the second embodiment according to  FIG. 3 ; 
       FIG. 4   a  is a plan view of a detail illustration of the Peltier element of the second embodiment according to  FIG. 3 ; and 
       FIGS. 5A-5G  are diagrammatic, sectional views showing an illustration of the production of the semiconductor component in a sandwich configuration. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring now to the figures of the drawing in detail and first, particularly, to  FIG. 1  thereof, there is shown a first embodiment of a semiconductor component  20  according to the invention. The semiconductor component  20  has a coupling device  3 , by which a Peltier element  1  and a thermogenerator element  2  are thermally coupled to one another. In this case, the coupling device  3  is formed as a highly doped silicon layer that serves as a thermal short circuit on account of high thermal conductivity. In this case, the Peltier element  1  and thermogenerator element  2  are formed as a sandwich component whose production is disclosed in Published, Non-Prosecuted German Patent Application DE 198 45 104 A1. The production, according to the invention, will be described in more detail in connection with FIG.  5 . 
   On the semiconductor component  20  there is disposed, as an optoelectronic component, a laser diode  10  in a hybrid design. In this case, the Peltier element  1  is disposed below the laser diode  10  and serves for cooling the laser diode  10 . Therefore, the left-hand side A of the semiconductor component  20  is also called the Peltier side. 
   In this case, the laser diode  10  is used as a microstructure  10 . In principle, however, it is also possible to dispose other microstructures, such as e.g. filters, gratings or else sensors on the coupling device  3  in order to regulate temperature by use of the semiconductor component  20  according to the invention. The microstructure may also be a depression that forms a microreactor. Microstructures whose temperature are to be regulated and which can be found in the field of biotechnology can also be disposed on the coupling device  3 . 
   On the right-hand side B of the semiconductor component  20 , the thermogenerator side, the thermogenerator element  2  serves for converting a temperature difference into a voltage. The temperature difference exists between the relatively hot laser diode  10  and the ambient temperature in this case. The voltage generated by the thermogenerator  2  can then be used to supply an integrated circuit  11 , which is disposed on the coupling device  3  for the purpose of driving the laser diode  10 . In the present exemplary embodiment, the integrated circuit  11  is disposed in a hybrid design on the coupling device  3 . 
   A thermistor  12  (NTC resistor) is used as measurement pickup for the integrated circuit  11 , the thermistor  12  in this case likewise being connected to the coupling device  3  in a hybrid design. 
   The semiconductor component  20  according to the invention thus has a compact combination of hitherto separate functional groups (Peltier cooler, thermogenerator). The thermogenerator  2  may serve for relieving the load on a non-illustrated external voltage source for the integrated circuit  11 . The thermogenerator  2  is integrated with the Peltier element  1 —required for cooling the laser diode  10 —in a component. 
   A circuit  21  required for smoothing the voltage of the thermogenerator  2  is disposed in the integrated circuit  11 . 
   The semiconductor component  20  on the Peltier side A and the thermogenerator side B is connected to a heat sink  13  via gold contacts  14  (gold bumps). 
   The laser diode  10  was used as the component to be cooled in the present example. In principle, the semiconductor component  20  according to the invention can also be used for cooling other optoelectronic components, such as, e.g. a laser-based gas sensor. 
     FIG. 2  diagrammatically represents the first embodiment of the semiconductor component  20  according to the invention in a perspective view. 
   In this case, the upper plane is formed by the silicon layer of the coupling device  3 ; situated underneath is the lower plane of the Peltier element  1  and of the thermogenerator element  2 . 
   The laser diode  10 , the integrated circuit  11  and the thermistor  12  are disposed in a hybrid design on the coupling device  3 . 
   The integrated circuit  11  is connected to the Peltier element  1 , the thermogenerator element  2 , the thermistor  12  and the laser diode  10  via lines  7 . 
     FIG. 2A  shows a plan view of the Peltier element  1 . 
     FIG. 3  illustrates a second embodiment of the semiconductor component  20  according to the invention. The basic construction corresponds to the first embodiment, and so reference may be made to the corresponding description of FIG.  1 . 
   In contrast to the first embodiment, in this case, the integrated circuit  11  and the thermistor  12  are incorporated as layer structures into the silicon of the coupling device  3 . Monolithic integration of the integrated circuit  11  and of the thermistor  12  is thus afforded. 
   In an alternative that is not illustrated here, the component  10  to be cooled may also be monolithically integrated into the coupling device  3 . 
     FIG. 4 , analogously to  FIG. 2 , illustrates a perspective view of the second embodiment of the semiconductor component  20  according to the invention. It can be seen in this case that the integrated circuit  11  and the thermistor  12  are integrated into the upper plane of the coupling device  3 . 
     FIG. 4A  shows once again a plan view of the peltier element  1 . 
     FIGS. 5A  to  5 G describe the production of a component in the form of a sandwich configuration. The sandwich component can then be used in a semiconductor component according to the invention as the Peltier element  1  and/or the thermogenerator element  2 . Other production methods for a thermoelectric transducer can be gathered from DE 198 45 104 A1 which is hereby incorporated herein. 
   A first electrically conductive layer  110  is produced on a main area  118  of a first substrate wafer  111 . The layer  110  contains e.g. a metal layer, a metal layer sequence or a highly doped and hence highly conductive semiconductor layer (e.g. diffused silicon). 
   The first substrate wafer  111  has a low electrical conductivity overall and contains, for example, semi-insulating silicon or has an electrically insulating layer  114  (e.g. a silicon oxide or silicon nitride layer) on the side of the main area  118 . 
   A layer  112  made of thermoelectric material (e.g. Bi 2 Te 3 , Bi 2 Se 3 , PbTe, Si, Ge, etc.) is deposited on the first electrically conductive layer  110  (see FIG.  5 A). A plurality of doped regions  140  of a first conductivity type (e.g. p-conducting) and a plurality of doped regions  150  of a second conductivity type (e.g. n-conducting) are subsequently formed in the layer  112  by use of photomask technology and diffusion (see FIG.  5 B). 
   The layer  112  with the doped regions  140 ,  150  is then patterned by using one or more photomask and performing etching processes known per se to form first bodies  40  and second bodies  50  (see FIG.  5 C). 
   The first electrically conductive layer  110  is then likewise patterned by use of a photomask and etching processes in such a way as to produce on the first substrate wafer  111  a plurality of mutually separate thermoelement cells ( FIG. 5C ) which each have a first body  40  and a second body  50  and a first electrical interconnect  30  connecting them (FIG.  5 D). 
   A metallization layer  130  (e.g. made of gold) is disposed on the sides of the first and second bodies  40 ,  50  opposite to the first interconnect  30 . 
   A second electrically conductive layer  122  is disposed on a main area  119  of a second substrate wafer  121  ( FIG. 5E ) and patterned to form second electrical interconnects  60  (FIG.  5 F). 
   Analogously to the first substrate wafer  111 , the second substrate wafer  121  has a low electrical conductivity overall and contains, for example, semi-insulating silicon. The second substrate wafer  121  may also have an electrically insulating layer  115  (e.g. a silicon oxide or silicon nitride layer) on the side of the main area  119 . 
   After the patterning of the second interconnects  60 , the second substrate wafer  121  is placed with the latter onto the metallization layers  130  of the first and second bodies  40 ,  50  and aligned in such a way that the second interconnects  60  bear on the metallization layers  130  of the first and second bodies  40 ,  50  and the previously formed pairs each containing a first and a second body  40 ,  50  are connected up to one another in series (FIG.  5 G). 
   The second electrical interconnects  60  and the metallization layers  130  are then connected to one another, e.g. by soldering, adhesive bonding or thermocompression. 
   This results in a sandwich composite containing the two substrate wafers  111 ,  121  and the thermoelement cells situated in between. 
   The embodiment of the invention is not restricted to the preferred exemplary embodiments specified above. Rather, a number of variants are conceivable which make use of the semiconductor component according to the invention in the case of embodiments of fundamentally different configuration too.