Analysis of the electrical characteristics of Mo/4H-SiC Schottky barrier diodes for temperature sensing applications

The experimental forward current–voltage–temperature (ID–VD–T) characteristics of Mo/4H-SiC Schottky barrier diodes are investigated by means of a careful simulation study. The simulations are in excellent agreement with measurements in the whole explored current range extending over ten orders of magnitude for temperatures from 303 K to 498 K. The diode ideality factor tends to decrease while the Schottky barrier height increases with increasing temperature. These variations are explained on the basis of the thermionic emission theory with a Gaussian distribution of the barrier height around the Mo/4H-SiC interface. The calculated Richardson constant is A* = 155.78 A cm−2 K−2 which is very close to the theoretical value of 146 A cm−2 K−2 expected for n-type 4H-SiC. The linear dependence of VD on temperature is also investigated for several bias currents. The obtained results reveal that the device is well suited for temperature-sensing applications, showing a good coefficient of determination (R2 = 0.99974 for 100 nA ≤ ID ≤ 1 mA) and a high sensitivity (S = 1.92 mV K−1 for ID = 1 μA). The temperature error between the voltage measurements and their linear best fit is lower than 1.5 K.