Design And Fabrication Of Blue/Violet Sensitive Si Photodetectors

According to the requirement of bionic micro-nano navigation sensor on detecting the blue-violet polarized light, which originates from the National Basic Research Program of China (Grant2011CB302101and2011CB302105), a novel blue/violet sensitive photodetector was prompted. Based on Lambert-Beer law and semiconductor device theory, its operational mechanism was analyzed in order to optimize the device structure. The spectral responsivity characteristics of designed photodetector were simulated and analyzed. The results showed that it had a good response in the range of blue-violet light while the responsivity of longer wavelength in the visible light and near infrared range had been repressed. Finally, the fabrication of designed photodetector was carried out.A measurement system used for characterizing the spectral responsivity of photodetector was designed and established. The results showed that the peak spectral responsivity of sample photodetector was at wavelength of460nm, which effectively realized the inhibition of the spectral reasponse to the longer-wavelength in visible spectral region and near infrared. The current-voltage characteristics of sample photodetectors were tested using semiconductor parameter test device (Kithley,4200-SGS). The dark current of the sample was about0.2nA, which satisfies the requirements of the research project basically.In order to realize the integration with logarithmic amplifier circuit, a CMOS-process-compatible blue/violet sensitive silicon photodetector was designed. The numerical calculation and theoretical analysis were performed. The results showed that the designed device has an excellent responsivity to blue/violet light. The quantum efficiency is more than0.4. So our designed photodetector is beneficial to reduce the volume of photodetector in order to avoid signal interference.