Stability of Electrical Properties of High-Temperature Operated H2 Sensor Based on Pt-I-SiC Diode

Pt–I–SiC diodes with a thin oxide layer were annealed for 6 h at 600 °C in air. Forward and reverse current–voltage (I–V) and capacitance–voltage (C–V) characteristics were measured in two ambients, 20% O2 in N2 and 20% H2 in N2 , at room temperature and 300 °C repeatedly. The parameters of the diode as ideality factor, series resistance, change in barrier height were evaluated as a function of the number of repetition times. Annealing has reduced the current, the capacitance and the gas sensitivity in the I–V characteristics, though the stability of the electrical properties of the I–V and C–V characteristics of the diode was maintained under temperature conditions lower than 300 °C. However, the gas sensitivity in the C–V characteristics was not affected by annealing. The results presented in this paper substantiate the possibility of formation of thin oxide layer at SiC surface as mechanism of the degradation of Schottky diode based on SiC.