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在GaAs外延层上用电子束蒸发Nb及直流等离子体溅射Mo和Au的办法,制备了GaAs-Nb-Mo-Au结构的肖脱基势垒二极管.用XPS结合氩离子刻蚀测量了它的成分深度分布及界面特性,得到:当溅射Mo层厚度大于1000 A时,Au和GaAs之间的互扩散可以被阻挡住.Mo向Nb中的扩散使单独的Nb层不复存在,二极管成为GaAs-(Nb,Mo、Ga、As)-Mo-(MoAu)-Au结构.在界面过渡区中,Mo以金属形式存在,而Nb则同GaAs表面的天然氧化层反应后生成为低价的氧化铌.MoNb-GaAs肖脱基势垒比Mo-GaAs结构热稳定性好的原因,可能是同Nb氧化物的高生成热相联系的.
A Schottky barrier diode of GaAs-Nb-Mo-Au structure was fabricated by electron-beam evaporation of Nb and direct current plasma sputtering of Mo and Au on the GaAs epitaxial layer. It was measured by XPS combined with argon ion etching The results show that the interdiffusion between Au and GaAs can be blocked when the thickness of the sputtered Mo layer is greater than 1000 A. The diffusion of Mo into Nb ceases to exist in the separate Nb layer and the diode (Mo, Ga, As) -Mo- (MoAu) -Au structure.In the interfacial transition region, Mo exists in the form of metal, while Nb reacts with the natural oxide layer on the GaAs surface to form a low-valent Niobium oxide. MoNb-GaAs Schottky barrier than Mo-GaAs structure thermal stability may be due to the high heat of Nb oxide associated.