N型SiC的Ni基欧姆接触研究

摘要

对n型SiC的Ni基欧姆接触的机理进行了研究.通过在P型4H-SiC外延层上使用N离子注入来形成N阱,并在此基础上制作Ni/n型SiC欧姆接触的TLM结构,得到的比接触电阻约为1.7X10-4Ω·cm2.合金化的高温退火过程导致了C空位(Vc)的出现,起到了施主的作用,降低了有效肖特基势垒高度,从而形成欧姆接触.通过模拟估计了有效载流子密度的增加,结果表明,高温退火中形成的C空位对于最终欧姆接触的形成起到了重要作用,甚至超过了掺杂水平的影响.%The Ni-based Ohmic contact to n-type SiC is studied.An array of TLM test patterns with Ni/n-type SiC structure is formed on N-wells created by Nion implantation into Si faced p-type 4H-SiC epilayer,which the specifevidence that C vacancy Vc,acting as donors,contributes to reduce effective Sehottky barrier height for the transport of electrons and form ohmic contact.The density of effective carriers provided by C vacancies can be estimated with the simulation based on the test pattern.It is found that the effect of C vacancies formed during the high temperature on the ohmic contact is more than the doping level.