A Novel Stepped Doping Substrate Structure to Improve the Response of THz CMOS Detector

In this paper, a novel stepped doping substrate structure is proposed for THz CMOS detector to improve the response. The stepped doping substrate employs a parasitism-reduction region to suppress the leaking current by decreasing the parasitic capacitance between the drain and the substrate and a plasma-wave transiting region to ensure the sensitive response of the channel potential to the THz signal. The operation mechanism of proposed structure has been investigated and the effects of related parameters have been discussed. The TCAD simulation results show that the parasitic capacitance of the novel structure can be decreased by more than 400% compared to the traditional NPN detector structure and the response of the detector can be improved by approximately 80% at 300 GHz.