Comparison of Ohmic Contact Characteristics of Different Metal on N Type 4H-SiC
Ohmic contact testing structures have been prepared on n type 4H-SiC layer with different multiple-layer metal, such as Ti/Ni/Au, Cr/Ni/Au and Ni/Ti/Au by magnetic sputter process. Special contact resistances about 10-6cm2 are achieved using TLM measurements. The composition of the alloy areas have been analyzed through XPS and AES, and the results show that the C vacancies induced by carbonides formation are important for ohmic contacts of Ti and Cr to SiC. However, the Ni/SiC structures need a relatively higher alloy temperature, so that the out diffusion of C atoms can offset the lack of Si in the top layer of SiC.
Zhengyi Jiang, Jingtao Han and Xianghua Liu
H. J. Jia et al., "Comparison of Ohmic Contact Characteristics of Different Metal on N Type 4H-SiC", Advanced Materials Research, Vols. 152-153, pp. 1529-1532, 2011