Schottky Barrier Height Analysis of Diamond SPIND Using High Temperature Operation up to 873 K

In this work, the high temperature performance of a diamond Schottky PIN diode is reported in the range of 298-873 K. The diamond diode exhibited an explicit rectification up to 723 K with an excellent forward current density of >3000 A/cm2. The stability of the diode was investigated by exposing the sample to high temperature cycles (up to 873 K) for more than 10 times (totaling up to 120 hours), which exhibited no change between the I-V characteristics measured in each cycle. The dependence of ideality factor and Schottky barrier height on temperature along with an extracted Richardson's constant much smaller than the theoretical value (0.0461 A/cm2.K2), motivated us to study the possible reason for this anomaly. A modified thermionic emission model following Tung's analysis was used to explain the experimental observations. The model assumed the presence of inhomogeneous Schottky barrier heights leading to a reduced effective area and yielded a Richardson's constant closer to the theoretical value. Conductive atomic force microscopy studies were conducted, which concurred with the electrical data and confirmed the presence of inhomogeneous Schottky barrier heights.