GaAs和(Cs,O)/GaAs热处理工艺的XPS研究  

XPS Studies of Thermally Cleaned Surfaces of GaAs and (Cs,O)/GaAs

作　　者：汪贵华[1] 房红兵[1] 

机构地区：[1]南京理工大学电子工程与光电子技术学院

出　　处：《真空科学与技术》2003年第5期307-310,共4页Vacuum Science and Technology

摘　　要：用X射线光电子能谱(XPS)研究了GaAs(100)面基片的化学清洗、热净化、(Cs,O)激活后加热的处理效果。GaAs的氧化过程是:首先,As氧化为低价态,然后Ga被氧化,再就是As氧化为高价。确保样品从刻蚀清洗到超高真空环境中,表面Ga没有被氧化,就可在较低的温度热净化,获得As稳定的且原子级清洁的GaAs表面。净化后GaAs表面Ga含量越高,则(Cs,O)激活后形成氧化物越多,从而形成了界面势垒,使电子逸出概率降低。Thermally-cleaned surfaces of GaAs(l00) and (Cs,O) GaAs films, used in photocathode fabrication, were studied with X-ray photoelectron spectroscopy (XPS) to understand the surface oxidation. The results show that Ga oxidization, occurring after As is first oxidized to low valence state, is followed by As oxidization to high valence state. As rich, atomically clean and stable GaAs surface can easily be obtained by chemical cleaning followed by thermal annealing at a rather low temperature as 625°C, if Ga oxidization is avoided. High Ga concentration favors the growth of Ga oxide in (Cs,O) activation. The surface barrier of Ga oxide considerably lowers the surface emission probability.

关 键 词：GAAS X射线光电子能谱 热净化 氧化 激活 

分 类 号：O485[理学—固体物理] O655.9[理学—物理]