Low specific contact resistance on epitaxial p-type 4H-SiC with a step-bunching surface  

作　　者：韩超 张玉明 宋庆文 汤晓燕 张义门 郭辉 王悦湖 

机构地区：[1]School of Microelectronics, Xidian University, Key Laboratory of Wide Band Gap Semiconductor Materials and Devices [2]School of Advanced Materials and Nanotechnology, Xidian University

出　　处：《Chinese Physics B》2015年第11期452-459,共8页中国物理B（英文版）

基　　金：supported by the Key Specific Projects of Ministry of Education of China(Grant No.625010101);the National Natural Science Foundation of China(Grant No.61234006);the Natural Science Foundation of Shaan Xi Province,China(Grant No.2013JQ8012);the Doctoral Fund of Ministry of Education of China(Grant No.20130203120017);the Specific Project of the Core Devices,China(Grant No.2013ZX0100100-004)

摘　　要：This paper reports the performances of Ti/Al based ohmic contacts fabricated on highly doped p-type 4H-SiC epitaxial layer which has a severe step-bunching surface. Different contact schemes are investigated based on the AI：Ti composition with no more than 50 at.% Al. The specific contact resistance （SCR） is obtained to be as low as 2.6 × 10-6Ωcm2 for the bilayered Ti（100 nm）/Al（100 nm） contact treated with 3 rain rapid thermal annealing （RTA） at 1000 ℃. The microstructure analyses examined by physical and chemical characterization techniques reveal an alloy-assisted ohmic contact formation mechanism, i.e., a high degree of alloying plays a decisive role in forming the interfacial ternary Ti3SiC2 dominating the ohmic behavior of the Ti/Al based contact. Furthermore, a globally covered Ti3 SiC2 layer with （0001）-oriented texture can be formed, regardless of the surface step bunching as well as its structural evolution during the metallization annealing.This paper reports the performances of Ti/Al based ohmic contacts fabricated on highly doped p-type 4H-SiC epitaxial layer which has a severe step-bunching surface. Different contact schemes are investigated based on the AI：Ti composition with no more than 50 at.% Al. The specific contact resistance （SCR） is obtained to be as low as 2.6 × 10-6Ωcm2 for the bilayered Ti（100 nm）/Al（100 nm） contact treated with 3 rain rapid thermal annealing （RTA） at 1000 ℃. The microstructure analyses examined by physical and chemical characterization techniques reveal an alloy-assisted ohmic contact formation mechanism, i.e., a high degree of alloying plays a decisive role in forming the interfacial ternary Ti3SiC2 dominating the ohmic behavior of the Ti/Al based contact. Furthermore, a globally covered Ti3 SiC2 layer with （0001）-oriented texture can be formed, regardless of the surface step bunching as well as its structural evolution during the metallization annealing.

关 键 词：4H-SIC P-TYPE ohmic contact ALLOYING step bunching 

分 类 号：TQ127.2[化学工程—无机化工]