A hybrid 6H-SiC temperature sensor operational from 25°C to 500°C

6H-SiC buried-gate n-channel depletion-mode junction field-effect transistors (JFETs) were characterized from 25°C to 350°C in terms of transconductance (g_m), pinchoff voltage (V_P ), output resistance (r_o), input resistance (R_in ), drain-to-source current at zero gate-to-source voltage (I_DSS), gate-to-source reverse biased leakage current (I_GSS), off-state drain-to-source current (I_DSS(off) ), and noise power spectral density (S_V). The 6H-SiC JFET´s were used in a hybrid temperature monitoring circuit (tested from -196°C to 500°C) fabricated at Auburn University for use in numerous industrial applications. Simulation program with integrated circuit emphasis (SPICE) simulations of the temperature monitoring circuit´s output voltage corresponded well with measured data as a function of temperature. Linear regression (LR) analysis of measured data revealed a notably sensitive (~2.3 mV/°), and an eminently linear (correlation coefficient =-0.0996...over 25°C to 500°C range) relationship between the measured output voltage and temperature. Below -50°C, the output became nonlinear, presumably from carrier freeze-out effects. To the best of our knowledge, this represents the first successful implementation of SiC active devices into a temperature sensor which demonstrated stable operation up to 500°C