Evidence of the Role of Carbon Vacancies in Nickel-Based Ohmic Contacts to n-Type Silicon Carbide  

n型SiC的Ni基欧姆接触中C空位作用的实验证明(英文)

作　　者：郭辉[1] 张义门[1] 张玉明[1] 

机构地区：[1]西安电子科技大学微电子学院

出　　处：《Journal of Semiconductors》2007年第1期5-9,共5页半导体学报（英文版）

基　　金：国家重点基础研究发展计划(批准号:2002CB311904);国家重点基础研究发展计划军用项目(批准号:51327010101);国家自然科学基金(批准号:60376001)资助项目~~

摘　　要：N-wells are created by P＋ ion implantation into Si-faced p-type 4H-SiC epilayer. Ti and Ni are deposited in sequence on the surface of the active regions. Ni2Si is identified as the dominant phase by X-ray diffraction （XRD） analysis after metallization annealing. An amorphous C film at the Ni2 Si/SiC interface is confirmed by an X-ray energy-dispersive spectrometer （XEDS）. The Ni2Si and amorphous C film are etched away selectively,followed by deposition of new metal films without annealing. Measurement of the current-voltage characteristics shows that the contacts are still ohmic after the Ni2 Si and amorphous C film are replaced by new metal films. The sheet resistance Rsh of the implanted layers decreases from 975 to 438f2/D, because carbon vacancies （Vc） appeared during annealing,which act as donors for electrons in SiC.通过在Si面p型4 H-SiC外延层上使用P+离子注入来形成n阱.Ti和Ni依次淀积在有源区的表面,金属化退火后的XRD分析结果表明Ni2Si是主要的合金相.XEDS的结果表明在Ni2Si/SiC界面处存在一层无定型C.去除Ni2Si合金相与无定型C之后重新淀积金属,不经退火即可形成欧姆接触.同时,注入层的方块电阻Rsh从975下降到438Ω/□.结果表明,合金化退火过程中形成了起施主作用的C空位(VC) .C空位提高了有效载流子浓度并对最终形成欧姆接触起到了重要作用.

关 键 词：NI ohmic contact silicon carbide carbon vacancies P^＋ ion implantation 

分 类 号：TN305[电子电信—物理电子学]