论文部分内容阅读
二氧化硅薄膜至今依然属人们广泛研究的材料,这是因为当这种材料制备为高质量的超薄、极薄的氧化物时,可实际应用于不同方面,如超大规模集成电路(VLSI)的栅氧化层以及液晶显示屏(LCD)的生产。本文考察了厚度为3nm和5nm的极薄二氧化硅层的结构性质,这些薄层是通过适度掺杂n-型硅(100)晶片而形成。在形成氧化层之前用标准RCA方法清洁,并随后在氮气氛围中退火,部分样品在HCN溶液中钝化。本研究中用傅立叶变换红外光谱(FT-IR)技术获取了复合结构中不同类型的化学键信息。对SiO2钝化试样和非钝化试样中的Si-O-Si的不对称伸缩振动分别用纵光(LO)和横光(TO)模式进行了鉴别,发现TO模式位置(约1 107cm-1)和振幅与试样的厚度无关。另一方面,LO模式的位置从约1 230cm-1(厚度约为1.5nm)改变为1 244cm-1左右(厚度约为4.5nm)。根据红外光谱峰的偏移,认为超薄和极薄SiOx复合结构并不均匀。对红外光谱获得的结果进行了反褶积处理并获取相关信息。用次级离子质谱分析法(SIMS,Secondary Ion Mass Spectrometry)考察了试样的原子组成,发现NH键的数量也与技术条件相关。基于记录的试样X-反射率数据的理论处理结果,用原始方法确定了材料的结构性质、层密度、表面粗糙度以及相应界面,并将所得结果与原子力显微镜所获得的结果进行了对比和讨论。借助于深能阶瞬态光谱学中的电荷变形,证实HCN溶液对二氧化硅/硅界面密度的强钝化影响。钝化后,发现新形成的界面深处缺陷阱其密度可以忽略不计,这是因为其形成原因与钝化过程中在界面处引入的NH原子对存在相关。
Silica films are by far the most widely studied material because of their practical applicability in various fields such as very large scale integrated circuits (VLSI) when they are made of high-quality ultra-thin, ultra-thin oxides, Gate oxide and liquid crystal display (LCD) production. This paper examines the structural properties of very thin silicon dioxide layers of 3 nm and 5 nm thick formed by the moderate doping of n-type silicon (100) wafers. The standard RCA method was used to clean the oxide layer and then annealed in a nitrogen atmosphere. Some samples were passivated in HCN solution. In this study, we used Fourier transform infrared spectroscopy (FT-IR) to obtain different types of chemical bond information in the composite structure. The asymmetric stretching vibration of Si-O-Si in SiO2-passivated and non-passivated samples was identified by LO and TO modes respectively. It was found that the TO mode position (about 1 107 cm- 1) and the amplitude is independent of the thickness of the specimen. On the other hand, the position of the LO mode is changed from about 1 230 cm -1 (thickness about 1.5 nm) to about 1 244 cm -1 (thickness about 4.5 nm). According to the shift of the infrared peak, it is considered that the ultra-thin and ultra-thin SiOx composite structure is not uniform. The results obtained by infrared spectroscopy were deconvolved and the relevant information was obtained. The atomic composition of the sample was examined by secondary ion mass spectrometry (SIMS). The number of NH bonds was also found to be related to the technical conditions. Based on the theoretical results of the recorded X-ray reflectivity data, the structural properties, layer densities, surface roughness and corresponding interfaces of the materials were determined by the original method. The results were compared with those obtained by atomic force microscopy discuss. With the charge distortion in deep-level transient spectroscopy, the strong passivation of the HCN solution to the silica / silicon interface density was demonstrated. After passivation, it was found that the density of the newly formed deep well defect at the interface is negligible because the reason for the formation is related to the presence of NH atoms introduced at the interface during passivation.