A method to improve the specific contact resistance of 4H-SiC Ohmic contact through increasing the ratio of sp~2-carbon

摘要

Generally, high temperature annealing treatment (＞950°C) is required to form Ni/SiC Ohmic contact. Some research believes that the specific contact resistance could be improved by the increase in sp~2-carbon at the Ni/SiC interface. In this work, a magnetron sputtering deposited carbon layer has been inserted into Ni/SiC and annealed at 850°Cto verify the effect of sp~2-carbon. The results indicate that the sp~2-carbon ratio increases from 31% to 66%, and the specific contact resistance improves from 2.5 × 10~(-4) Ω cm~2 to 5.0 ×10~(-5)Ω cm~2 with the insertion of carbon. Furthermore, the intermediate semiconductor layer (ISL) model is used to analyze the impacting mechanism of sp~2-carbon on Ohmic contact.