Evaluation of a Silicon Carbide Static Induction Transistor for High Frequency/High Temperature Sensor Interface...

In this paper, we report on the characterization of a silicon carbide static induction transistor (SiC SIT) for potential use in sensor interface circuits that operate at frequencies up to 100 MHz and temperatures up to 400 °C. Measurements were performed to generate current-voltage curves, capacitive transistor characteristics, and high-frequency scattering parameters at temperatures between 25 and 400 °C. The measured data were used to extrapolate the transconductance, g_m, as a function of temperature and to develop a small signal model. Circuit simulation tools were used to generate scattering parameters, which were compared to the measured values. At 400 °C, the maximum difference between the measured and simulated scattering parameters for frequencies from 20 to 100 MHz were all less than 0.1 dB, indicating strong agreement between the model and measurement results. The average transition frequency, f_t, calculated from measured parameters was 197.8 MHz, which compares favorably to the simulated value from the model (200 MHz). This is also the first paper to report the characterization of a SiC SIT at temperatures above 100 °C. The high-temperature model is the first of its kind for a silicon carbide static induction transistor and the findings reported herein provide a platform to stimulate further development for sensor interface circuits that require transistors that operate at both high frequency and high temperature.