ULTRA-SMALL LOCOS PROCESS FOR Si QUANTUM DOT FORMATION

我研究了真空热氮化在Si (111) 7x7表面上的SiN成核及其对Si量子点形成的热氧化掩蔽效应。作为氧化条件，采用真空蚀刻方式氧化和炉内膜生长方式氧化。结果，发现了以下事实。厚度约为0.5nm的氮化物对蚀刻模式氧化具有较强的免疫力，形成Si柱。高度随氧化时间线性增加。氮化物还可以作为炉膛氧化的氧化面罩，将样品从真空中带到空气中。结果表明，该方法在柱和点的形成中是有效的。柱的尺寸和密度与SiN核的尺寸和密度相对应，在600-650℃较低的温度范围内氮化得到纳米级结构。下一步是将该工艺应用于SOI衬底，用于制造正在研究的Si点阵列。

I have studied SiN nucleation on Si (111) 7x7 surface by thermal nitridation in vacuum and its masking effects against thermal oxidation for Si quantum dot formation. As oxidation conditions, etching mode oxidation in vacuum and film growth mode oxidation in a furnace were employed. As a result, following facts were found.1. The nitrides, of which the thickness is about 0.5nm, have strong immunity against etching mode oxidation, resulting Si pillar formation. The height linearly increases with oxidation time.2. The nitrides also work as oxidation masks for furnace-oxidation by taking the sample out of vacuum to the air. This result indicates that the proposed process is useful and effective in pillar and dot formation.3. The size and density of pillars are corresponding to those of SiN nuclei and nm-scale structure is obtained by nitridation in a relatively low temperature range of 600-650C.The next step is to apply this process to SOI substrates for fabricating Si dot arrays, which is being studied.