Layr-by-layr oxidation mechanism of hydrogen-terminated silicon surfaces and their interface structures

氢封端硅表面逐层氧化机理及其界面结构

• 批准号: 04452177
• 负责人: HIROSE Masataka
• 金额: $ 4.42万
• 依托单位: HIROSHIMA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (B)
• 财政年份: 1992
• 资助国家: 日本
• 起止时间: 1992 至 1993
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-04452177/
• 关键词: Silicon surface; Surface microroughness; Hydrogen-terminated Si; Atomic step structure; Layr-by-layr oxidation; SiO_2; Si interface; FT-IR-ATR; AFM; 原子間力顕微鏡; 表面モフォロジー; layer by layer酸化; LOフォノン; 圧縮性応力; 表面酸化; 全反射赤外吸収分析; Silicon surface; Surface microroughness; Hydrogen-terminated Si; Atomic step structure; Layr-by-layr oxidation; SiO_2; Si interface; FT-IR-ATR; AFM; 原子間力顕微鏡; 表面モフォロジー; layer by layer酸化; LOフォノン; 圧縮性応力; 表面酸化; 全反射赤外吸収分析

It was found that the wet chemical treatment in a pH-modified BHF(pH=3.8)solution or a 0.1%HF+1%H_2O_2 solution significantly reduces the surface microroughness of Si(100)wafers as demonstrated by a sharp SiH_2 stretching vibration peak accompanied with the weak SiH and SiH_3 peaks in FT-IR-ATR spectra. The suppression of anisotropic etching of Si with OH ions in a BHF solution or the selective removal of chemically reactive sites on the surfaces by the oxidation with H_2O_2 followed by oxide etching with HF is thought to be effective to produce the flat Si(100) surface. Taking into account the fact that the native oxidation rate of the flat Si(100)surface is significantly suppressed in the early stages of the oxidation compared with the case of rough Si(100)surfaces, it is likely that the native oxidation starts to proceed from the chemically reactive site such as microfacets and step edges on the surface.The Si(111)surface becomes atomically flat by 40%NH_4F treatment. The bilayr atomic step structure with a terrace width of a few hundreds nm is clearly observed by AFM.The AFM image of the Si(111)surface covered with a 4nm-thick thermal oxide is almost identical to the surface morphology before oxidation and the step structure is still observable on the oxide. Also, the Si surface after the removal of the oxide by dilute HF is similar to the intial surface. This suggests that the oxidation of the Si(111)surfaces proceeds through a layr-by-layr mechanism and this might be the case also for Si(100)surfaces. Furthermore, it was found that the infrared absorption peak due to the LO phonon mode originating from the Si-O-Si stretching vibration shows a considerable red-shift in the thickness range below 25A.This red-shift is well explained by the existence of the compressive stress near the interface.

发现在pH修饰的BHF（pH = 3.8）溶液中的湿化学处理或0.1％HF+1％H_2O_2溶液显着降低了Si（100）晶圆的表面微度（通过Sharp Sih_2伸展振动峰伴随弱SiH_3峰和SIH_3峰的SiH_2升峰表现为ft-ir-ir-ir-ir-ir-ir-ir-ir-rrrra rra rrra rrra rra rrra rra rrra rrra rra rrrra rra rrrra rra rrrra。通过用H_2O_2的氧化作用，将SI用OH离子抑制Si在BHF溶液中使用OH离子抑制化学反应性位点在表面上的化学反应性位点，然后用H_2O_2氧化，然后用HF氧化物蚀刻HF蚀刻可以有效地产生平面Si（100）表面。考虑到一个事实，即与粗糙的Si（100）表面相比，在氧化的早期阶段，平面Si（100）表面的天然氧化速率受到了显着抑制，因此，本地反应性位点可能会从化学反应性的位点开始进行，例如微型机构和表面上的台阶。 AFM清楚地观察到具有露台宽度为几百nm的Bilayr原子步骤结构。Si（111）表面的AFM图像在氧化之前几乎与表面形态相同，并且在氧化物上仍然可以观察到步骤结构。同样，通过稀释的HF去除氧化物后的Si表面与Intial表面相似。这表明Si（111）表面的氧化是通过逐层机制进行的，而Si（100）表面也可能是这种情况。此外，发现源自Si-O-SI拉伸振动的LO声子模式引起的红外吸收峰表明，厚度范围低于25a的厚度范围相当大的红移。这种红移源于界面附近的压缩应力很好地解释了这种红移。