A 4H-SiC NMOSFET-Based Temperature Sensor Operating Between 14K and 481 K

The experimental characteristics of a temperature sensor based on a 4H-SiC diode-connected lateral NMOSFET are shown in the range between 14K and 481K. The device is fully compatible with 4H-SiC CMOS technology. The analysis of the sensor characteristics reveals a main temperature dependence on the threshold voltage compared to the channel mobility. Due to the oxide/semiconductor interface traps, the sensor characteristic is divided in three temperature ranges to obtain a good linearity: in 14K ≤ T ≤ 200K, the sensitivity is 53.46mV/K, the rms error is 5.49K and the coefficient of determination is 0.9927 for a bias current of 1.59μA; instead, a current of 100μA permits to have a maximum coefficient of determination of 0.9708 with a sensitivity of 29.9mV/K for 200K < T ≤ 394K, and a linearity of 0.9926 with a sensitivity of 13.72mV/K at T > 394K. Finally, for currents between 870nA and 9μA the linearity is higher than 0.95 in all temperature ranges.