Device scaling of pseudo-vertical diamond power Schottky barrier diodes

摘要

Device size scaling of pseudo-vertical diamond Schottky barrier diodes (SBDs) has been characterized for high-power device applications based on the control of doping concentration and thickness of the p~- CVD diamond layer. Decreasing parasitic resistance on the p~+ layer utilising lithography and etching realises a constant specific on-resistance of less than 20 m OMEGA cm~2 with increasing device size up to 200 mu m. However, the leakage current under low reverse bias conditions is increased markedly. Due to the increase in the leakage current, the reverse operation limit is decreased from 2.4 to 1.3 MV/cm when the device size is increased from 30 to 150 mu m. If defects induce an increase in leakage current under the reverse conditions, the density of the defects can be estimated to be 10~4-10~5/cm~2. This value is 5-10 times larger than the density of dislocations in single crystal diamond 1b substrate.