NH3等离子体钝化对Al2O3/SiGe界面的影响

研究了不同条件的非原位NH_3等离子体钝化对Al_2O_3/SiGe/Si结构界面组分的影响。在p型Si(100)衬底上外延一层30 nm厚的应变Si_0.7Ge_0.3,采用双层Al_2O_3结构,第一层1 nm厚的Al_2O_3薄膜为保护层,之后使用非原位NH_3等离子体分别在300和400℃下对Al_2O_3/SiGe界面进行不同时间和功率的钝化处理,形成硅氮化物(SiN_xO_y)和锗氮化物(GeN_xO_y)的界面层。通过X射线光电子能谱(XPS)分析表面的物质成分,结果表明NH_3等离子体钝化在界面处存在选择性氮化,更倾向于与Si结合从而抑制Ge形成高价态,这种选择性会随着时间的增加、功率的增高和温度的升高变得更加明显。

Effects of NH_3 Plasma Passivation on the Interface of Al_2O_3/SiGe

Effects of different conditions of ex-situ NH3 plasma passivation on the interfacial component of Al2O3/SiGe/Si structure were investigated. A layer of strained-Si0.7Ge0.3 with a thickness of 30 nm was epitaxially grown on the p-type Si(100) substrate. A double-layer Al2O3 structure was adop-ted, the first Al2O3 film with a thickness of 1 nm was deposited as a protective layer. After that, the interface of Al2O3/SiGe was passivated to form an interface layer of SiNxOy and GeNxOy by using ex-situ NH3 plasma with different time and power at 300 and 400 ℃, respectively. X-ray photoelectron spectroscopy(XPS) was used to analyze components of the interface. The results show that NH3 plasma treatment has the selective nitridation at the interface. It is more inclined to combine with Si to inhibit the formation of high valence states of Ge. This selectivity becomes more obvious with the increase of time, power and temperature, respectively.