重掺杂p型SiC晶片Ni/Al欧姆接触特性

Ni/Al Ohmic Contact Properties of Heavily Doped p⁃Type SiC Wafers

系统研究了Al和Ni/Al两种金属体系在重掺杂p型SiC晶片上的欧姆接触特性和电学性质。利用X射线衍射、扫描电子显微镜和综合物性测量系统对这两种电极表面的微观结构和样品的电学性质进行了表征。结果表明:在真空环境下经过800℃退火后Al电极可呈现出欧姆接触行为,其比接触电阻率为1.98×10^(-3)Ω·cm^(2),退火处理后Al电极与SiC在接触界面形成化合物Al_(4)C_(3),有助于提高接触界面稳定性。在Ni/Al复合体系中,当Ni金属层厚度为50 nm时,其比接触电阻率显著降低至4.013×10^(-4)Ω·cm^(2)。退火后Ni与SiC在接触界面生成的Ni_(2)Si有利于欧姆接触的形成和降低比接触电阻率。研究结果可为开发液相法生长的p型SiC晶片电子器件提供参考。

The ohmic contact properties and electrical characteristics of Al and Ni/Al on heavily doped p⁃type SiC wafers were systematically investigated.The microstructures of the two kinds of elec⁃trodes surface and electrical characteristics of the samples were characterized by X⁃ray diffraction,scan⁃ning electron microscopy and the integrated physical measurement system.The results show that the Al electrode can exhibit ohmic contact behavior after annealing at 800℃in vacuum,and its specific contact resistivity is 1.98×10^(-3)Ω·cm^(2).The formation of compound Al_(4)C_(3)at the contact interface between Al electrode and SiC after annealing treatment can promote the stability of the contact interface.In the Ni/Al composite system,the specific contact resistivity of the composite electrode with the Ni metal layer of 50 nm is significantly reduced to 4.013×10^(-4)Ω·cm^(2).It is found that the Ni_(2)Si gene⁃rated at the interface between Ni and SiC after annealing favors the formation of ohmic contact and the reduction of specific contact resistivity.The research results can provide reference for the development of electronic devices based on p⁃type SiC wafers grown by liquid⁃phase method.