Analysis of current-voltage-temperature characteristics in SiC Schottky diodes using threshold-accepting simulated-annealing techniques

Because of their high switching speeds and low power losses, metal-SiC Schottky-barrier diodes (SBD) are important to high performance, high temperature, and high frequency applications in power electronics. The use of 4H-SiC in SBDs is particularly advantageous because it has higher electron mobility than other SiC polytypes. However, due to surface non-homogeneity, the current-voltage characteristics of SiC SBDs are mostly non-ideal, and conventional analysis based on simple thermionic theory often leads to erroneous conclusions. In this work, we examine current-voltage-temperature properties of Ti on 4H-SiC SBDs and develop fitting algorithms to extract diode parameters based on non-uniform barrier height analysis approaches. These algorithms are based on "threshold-accepting simulated-annealing" techniques. The fitting yields a parameter set that is argued to better describe diode behavior: this parameter set is suggested to replace the average barrier height and the ideality factor often obtained from conventional Schottky diode analysis.