Simulation and analysis of the current-voltage-temperature characteristics of Al/Ti/4H-SiC Schottky barrier diodes

The current-voltage characteristics of Al/Ti/4H-SiC Schottky barrier diodes (SBDs) have been investigated in the 85 445 K temperature range by means of a combined numerical and analytical simulation study. Simulation results showed a good agreement with measurements in the whole explored current range from 10 µA to 10 mA. The main device electrical parameters, namely the barrier height and ideality factor, were found to be strongly temperature-dependent. In particular, the ideality factor decreases while the barrier height increases with increasing temperature. The observed behaviours have been successfully interpreted by using the thermionic emission (TE) theory with a triple Gaussian distribution of the barrier height (BH) in three different temperature ranges, i.e. 85 ≤ ΔT1 ≤ 135 K, 180 ≤ ΔT2 ≤ 270 K, and 315 ≤ ΔT3 ≤ 445 K. The corresponding Richardson constants are A1* = 149.26 A·cm-2K-2, A2* = 138.19 A·cm-2K-2, and A3* = 173.21 A·cm-2K-2, respectively. These values are close to the theoretical result of 146 A·cm−2K−2 expected for n-type 4H-SiC. Finally, it has been highlighted that the current flowing through the Schottky junction is also determined by the thermionic field emission (TFE) mechanism.