A 4H-SiC n-p-n Phototransistor With On-Line Temperature Monitoring Characteristic

Aiming for the temperature drift phenomenon of SiC phototransistor during ultraviolet detection process, the p-n junction is integrated into the 4H-SiC n-p-n phototransistor chip to enable on-line temperature monitoring characteristic in this work. The SiC phototransistor is fabricated and investigated. Basic characteristics testing results demonstrate that the device’s peak ultraviolet wavelength is 342 nm, with a peak responsivity of 6.92 mA/W at zero bias. When the temperature increases from room temperature (RT) to 300 °C, the ultraviolet responsivity increases by approximately 64.7 times. However, temperature characteristics of the experimental results demonstrate that the device has temperature-sensing capability under reverse biased conditions. When the current is constant, the reverse voltage shows good linearity with temperature, with a sensitivity of approximately 2.76 mV/°C at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$- 0.1~\mu $ </tex-math></inline-formula> A. The dynamic characteristics testing in a resistive load circuit demonstrates that the phototransistor has achieved on-line temperature monitoring ability. The equation between reverse current and temperature is also established for temperature extraction.