影响WSi_x与GaAs接触特性的因素

Factors of Influencing WSi_x/n-GaAs Contact Characteristics

自对准工艺可以降低GaAs FET的源漏电阻,提高跨导和截止频率.难熔金属硅化物WSi_x可用于自对准工艺.为得到较好的与GaAs接触的肖特基势垒特性和高温稳定性,本文较详细地实验研究了影响WSi_x与GaAs接触特性的诸因素,指出,除表面态外,主要有三种因素使WSi_x与GaAs之间的肖特基势垒二极管(SBD)性能变差:(1)Si在WSi_x中的含量;(2)界面情况——存在于GaAs表面的天然氧化层、退火后的互扩散和界面上生成的化合物;(3)溅射淀积WSi_x薄膜前,GaAs表面薄层的晶格状态.第三种因素对SBD性能的影响是在最近的实验中得到的.

The factors of influencing WSix/n-GaAs Schottky contact characteristics are investigated experimentally. They are found to bo (1) Si content in WSix, (2) interface situation including the natural oxide in GaAs surface, the interdiffusion and interfacial compounds after annealing, and (3) the lattice state of the thin layer at GaAs surface before WSix sputtering, to which a special discussion is given.