Abstract:
A signal boosting apparatus and a method of boosting signals applied in the MEMS are disclosed. The signal boosting apparatus includes a substrate, an oxide layer, and a signal transmission layer. The substrate has a doped region. The doped region has a plurality of conductive carriers. These conductive carriers have the same polarity as an electronic signal. The oxide layer is located on the substrate, and the signal transmission layer is located on the oxide layer. The signal transmission layer can receive and boost the electronic signal.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No(s). 102108324 filed in Taiwan, R.O.C. on Mar. 8, 2013, the entire contents of which are hereby incorporated by reference. 
       TECHNICAL FIELD 
       [0002]    The disclosure relates to a signal boosting apparatus and a method of boosting signals, and more particularly to a signal boosting apparatus and a method of boosting signals, which are adapted to a micro-electromechanical apparatus and are capable of preventing an electronic signal from signal loss. 
       BACKGROUND 
       [0003]    For the semiconductor fabrication of semiconductor devices, metal layers and oxide layers are very commonly used. Take a micro-electromechanical system (MEMS) device as an example. The MEMS device usually has metal layers and oxide layers layered and can integrate an application-specific integrated circuit (ASIC) and a MEMS together in the same surface, thereby simplifying its packaging process. However, between the MEMS device and the material of its peripheral structure the parasitic effect exists. 
         [0004]    To produce a MEMS device, its mechanical structure has to be transformed to an equivalent circuit, and then this equivalent circuit will be integrated with the ASIC to produce a system-on-chip (SoC). However, most MEMS devices usually are constructed on silicon substrates. When electronic signals are transmitted in the MEMS device, parasitic capacitors may be formed between the MEMS device and the silicon substrate. Therefore, a part of the electronic signal may flow in the silicon substrate and become lost. In other words, such parasitic capacitors may reduce the intensity of the electronic signal traveling in the MEMS device, that is, reduce the output power of the electronic signal. Moreover, such parasitic capacitors may complicate the design of a next stage of signal processing circuits. 
       SUMMARY 
       [0005]    According to one or more embodiments, the disclosure provides a signal boosting apparatus adapted to a micro-electromechanical apparatus. In one embodiment, the signal boosting apparatus may include a substrate, an oxide layer, and a signal transmission layer. The substrate may have a doped region where there are conductive carriers whose polarities are equal to a polarity related with an electronic signal. The oxide layer is located on the substrate. The signal transmission layer is located on the oxide layer, and is configured to receive and boost the electronic signal. 
         [0006]    According to one or more embodiments, the disclosure also provides a method of boosting signals, adapted to a micro-electromechanical apparatus. In one embodiment, the method may include the following steps. First, dope impurity atoms into a doped region of a substrate where there may be conductive carriers whose polarities are equal to a polarity related with an electronic signal. Then, form an oxide layer on the substrate, and on the oxide layer, form a signal transmission layer for receiving and boosting the electronic signal. 
         [0007]    The disclosure dopes impurity atoms in the doped region of the substrate to make the polarities of the conductive carriers in the doped region equal to the polarity related with the electronic signal in the signal transmission layer, so repulsion may occur between the substrate and the signal transmission layer. Therefore, the electronic signal may be prevented from the signal loss, to enhance the intensity of the electronic signal to increase the output power of the electronic signal, and the signal processing circuits may also be simplified. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The present disclosure will become more fully understood from the detailed description given herein below for illustration only, and thus does not limit the present disclosure, wherein: 
           [0009]      FIG. 1A  is a schematic view of a signal boosting apparatus in the disclosure; 
           [0010]      FIG. 1B  is a schematic view of a parasitic equivalence circuit in  FIG. 1A ; and 
           [0011]      FIG. 2  is a flow chart of a method of boosting signals in the disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawings. 
         [0013]      FIG. 1A  is a schematic view of a signal boosting apparatus  100  in the disclosure. The signal boosting apparatus  100  may be adapted to a micro-electromechanical apparatus such as a microphone, a pressure sensor, an altimeter, a flowmeter, or a tactile sensor. That is, the signal boosting apparatus  100  may be implemented in the structure of the micro-electromechanical apparatus. The signal boosting apparatus  100  may include a substrate  110 , an oxide layer  120 , and a signal transmission layer  130 . 
         [0014]    The substrate  110  may have a doped region  111  where there are conductive carriers whose polarities are equal to the polarity related with an electronic signal. In the doped region  111 , there are impurity atoms  112  which belong to, for example, Group 5 or Group 3. These conductive carriers may be electrons or holes. In one embodiment, while the doped impurity atoms  112  in the doped region  111  belong to Group 3, these conductive carriers are holes; and alternately, while the doped impurity atoms  112  in the doped region  111  belong to Group 5, these conductive carriers are electrons. For example, the substrate  110  may be a P type or N type silicon substrate. 
         [0015]    The oxide layer  120  may be located on the substrate  110 . In one embodiment, the oxide layer  120  may be formed through the thin film deposition. The signal transmission layer  130  may be located on the oxide layer  120  and be capable of receiving and boosting the electronic signal. 
         [0016]    The signal transmission layer  130  may include a mass block  132  and a plurality of cantilevers  134  coupled with the mass block  132 . The electronic signal may be transmitted from the mass block  132  to the cantilevers  134 . For example, the mass block  132  may be made of polycrystalline silicon or another possible material with a small thermal expansion coefficient, and the cantilever  134  may be metallic or metalloid. 
         [0017]    Take the Group 5 element as the impurity atoms  112 . The impurity atoms  112  may be doped in the doped region  111  via an ion implanter or an impurity diffuser, but the disclosure will not be limited thereto, Since the impurity atoms  112  belonging to Group 5 present the attribute of electrons, the conductive carriers in the doped region  111  are electrons whose polarities are negative. In this equivalent circuit, when the electronic signal carrying negative charges flows in the signal transmission layer  130 , since repulsion may occur between the electronic signal and the substrate  110 , the electronic signal may only be transmitted through the signal transmission layer  130 . 
         [0018]    Accordingly, via the design of the doped region  111  of the signal boosting apparatus  100 , the oxide layer  120  between the substrate  110  and the signal transmission layer  130  may be prevented from forming parasitic capacitors, to prevent the electronic signal from the signal loss flowing toward the substrate  110 , so that the intensity of the electronic signal may be enhanced or maintained. 
         [0019]    Referring to  FIG. 1B , a parasitic equivalence circuit in  FIG. 1A  is shown. The substrate  110  may be equivalently determined as a parasitic resistor R 1  and a parasitic capacitor C 1 . The oxide layer  120  may be equivalently determined as a parasitic capacitor C 2 . The signal transmission layer  130  may be equivalently determined as a parasitic resistor R 2 , a parasitic resistor R 3 , and a parasitic capacitor C 3 . Specifically, the parasitic resistor R 2  may be formed based on the mass block  132 , and the parasitic resistor R 3  may be formed based on the cantilevers  134 . The connection between each of the parasitic resistors R 1 , R 2  and R 3  and each of the parasitic capacitors C 1 , C 2  and C 3  may be referred to what is shown in  FIG. 1B , and thus will not be repeated hereinafter. 
         [0020]    Accordingly, for the signal boosting apparatus  100 , since the electronic signal may be transmitted in the signal transmission layer  130 , the electronic signal may be prevented from flowing toward the substrate  110 . In other words, the electronic signal may be transmitted to the output end through the parasitic resistor R 2 , the parasitic capacitor C 3 , and the parasitic resistor R 3  rather than through the parasitic capacitor C 2 , the parasitic resistor R 1 , and the parasitic capacitor C 1 . In this way, the electronic signal may be prevented from the signal loss, so that the intensity and output power of the electronic signal may be maintained or enhanced. 
         [0021]      FIG. 2  is a flow chart of a method of boosting signals in the disclosure. Take a silicon substrate as the substrate  110 . First, as shown in step S 210 , dope the impurity atoms  112  in the doped region  111  of the substrate  110 . In one embodiment, the impurity atoms  112  may be doped into the substrate  110  via a doping apparatus such as an ion implanter or an impurity diffuser, but the disclosure will not be limited thereto. 
         [0022]    In this case, in doped region  111 , there are conductive carriers whose polarities are equal to the polarity related with the electronic signal. The doped impurity atoms  112  may belong to Group 5 or Group 3, and thus, the conductive carriers may be electrons or holes. That is, while the doped impurity atoms  112  belong to Group 3, the conductive carriers are holes, and while the doped impurity atoms  112  belong to Group 5, the conductive carriers are electrons. 
         [0023]    Then, as shown in step S 220 , form the oxide layer  120  on the substrate  110 . In one embodiment, the oxide layer  120  may be formed through the thin film deposition. Finally, on the oxide layer  120 , form the signal transmission layer  130  for receiving and boosting the electronic signal (step S 230 ). This signal transmission layer  130  may include the mass block  132  and the cantilevers  134  coupled with the mass block  132 , and thus, the electronic signal may be transmitted to the cantilevers  134  through the mass block  132 . For example, the mass block  132  may be made of polycrystalline silicon or other possible material with a small thermal expansion coefficient, and the cantilever  134  may be metallic or metalloid. 
         [0024]    Accordingly, the method may prevent the oxide layer  120  between the substrate  110  and the signal transmission layer  130  from parasitic capacitors, to prevent the electronic signal from the signal loss flowing toward the substrate  110 , to enhance or maintain the intensity of the electronic signal. 
         [0025]    As set forth above, the disclosure, providing the signal boosting apparatus and the method of boosting signals, may dope impurity atoms in the doped region of the substrate to make the polarities of the conductive carriers in the doped region equal to the polarity related with the electronic signal in the signal transmission layer, so repulsion may occur between the substrate and the signal transmission layer. Therefore, the electronic signal may be prevented from the signal loss, to enhance the intensity of the electronic signal to increase the output power of the electronic signal, and the signal processing circuits may also be simplified.