Low Specific Contact Resistance TiNb Ohmic Contacts to 4H-SiC with Laser Annealing for Harsh Environment Applications

摘要

SiC with large bandgap, high electric field strength, high thermal conductivity, and high mobility of charge carriers,etc., has been the potential candidate for high-power, high-temperature, high frequency, and hard radiation device applications. Jennings et al. reported that low specific contact resistance is critical problem for minimizing power lossless in the highpower devices as well as improvement high switching speed in the high frequency devices. Recently, Ti has been reported to be one of the best candidates to form ohmic contact to 4H-SiC. It has been reported that laser annealing has many advantages over rapid thermal annealing (RTA) to form ohmic contact to SiC. Milantha et al. fabricated Ti/4H-SiC ohmic contact with laser annealing with the lowest specific contact resistivity of 4.0 × 10~(-4)Ωcm~2. However, TEM images showed that the carbon agglomerationwas still observed, which was believed to cause the degradation of the contacts when operating in high power and high temperature environments. It has been indicated that Nb is a good candidate to collect the excess carbon atoms and thus improve the quality of the contacts.