GaAs/Si界面的化学态的研究

利用俄歇峰形分析技术对GaAs/Si界面的化学态和电子态进行了研究。提出了一种新的俄歇信号强度标定法——频域法。该方法利用低能俄歇电子较低的逸出深度,在复频域内标定来自最表层原子的俄歇信号强度,避免了二次电子本底和电子逸出平均自由程的影响,从而可以准确判定在界面这种突变结构中元素成分的深度分布信息。利用谱峰修正技术,研究了Ga、As、Si价带跃迁几率在界面不同深度内的变化情况,发现在界面处As-Si有明显的成键作用,Si原子的一部分p电子转移到了As原子空的p轨道中,由此产生了一个新的界面态,该界面态位于GaAs价带顶上方2eV的地方。在对Ga原子价带俄歇跃迁几率进行的研究中,并未发现其价电荷分布有明显的变化,表明Ga原子与其他原子在界面处并未发生明显的成键作用。

CHEMICAL STATES OF GaAs/Si INTERFACE

Auger lineshape analysis is employed in the study of chemical and electronic states of GaAs/Si interface. A fast Fourier transform algorithm is applied to quantitatively analyze the concentration of a particular element in an interrupted structure such as interface and surface. By correction of the Auger lineshape, we analyze the change of the Auger radial matrix elements for the CVV and CCV transitions of Ga, As, Si in different depth profiles of interface. It has been found that the Si bonds predominantly to As instead of Ga. Some p electrons are transferred from Si to the valance band of As, and a new interface state has emerged at 2eV ahove the top of the valance hand of GaAs. However for Ga, no significant changes are observed, maybe Ga has no bonding with Si in GaAs/Si interface.