【摘要】 用X射线光电子能谱仪 (XPS)研究了砷化镓 (GaAs)晶片在空气中的热氧化和在紫外光 臭氧激发下的氧化反应 .分析了氧化层中的微观化学构成、表面化学计量比以及表面氧化层的厚度等 .研究表明 ,两种氧化方法的氧化过程不同 ,在砷化镓表面形成的氧化膜的厚度以及组成也不同 ,热氧化下氧化层主要由Ga2 O3、As2 O3、As2 O5 以及少量元素As组成 ,而且表面明显富镓 ;紫外光激发下生成的氧化物主要为Ga2 O3 和As2 O3 ,镓砷比与本体一致 .讨论了可能的反应机理 ,紫外光不仅将氧分子激发为激发态氧原子 ,增加了氧的反应活性 ;同时也激发了GaAs材料的价电子 ,使其更容易被氧化更多还原

【Abstract】 X-ray photoelectron spectroscopy (XPS) wa s used to study two different oxidation treatments on the GaAs (100) surface——th e thermal oxidation in the air, and the ultraviolet-light oxidation in the UV- ozone. A series of properties including the oxide composition, chemical stat es, the surface Ga/As atomic ratio and the thickness of the oxide layer grow n on GaAs surface were compared. The results indicate that the oxide composition , the surface Ga/As atomic ratio and the thickness of the oxide layer oxide on G aAs surface are different for different oxidation methods. The oxides on GaAs su rface grown by thermal oxidation in the air are composed of Ga 2O 3, As 2O 5 , As 2O 3 and elemental As; and the Ga/As atomic ratio is drifted off the stoi chiometry far away. The Ga/As atomic ratio of oxide layer on GaAs surface is inc reases with the thickness of oxide. However, the oxides on GaAs surface grown by UV-ozone are made up of only Ga 2O 3 and As 2O 3, As 2O 5 and elemental As are not detected, the Ga/As atomic ratio is close to unity. The thickness of oxide layer on GaAs can be controlled by the UV exposing time. The mechanism of oxidation of GaAs is also discussed. The UV-light radiation not only causes the oxygen molecular excited forming atomic oxygen, but also induces the valenc e electrons of the GaAs excited from the valence band, and then the reactivity o f Ga and As atom increase, and they can easily react with the excited atomic oxy gen at the same reactive velocity.更多还原