ULTRA-SMALL LOCOS PROCESS FOR Si QUANTUM DOT FORMATION

研究了真空热氮化SiN在Si（111）7 x7表面的成核及其对热氧化的掩蔽作用。作为氧化条件，采用真空中的蚀刻模式氧化和炉中的膜生长模式氧化。结果发现以下事实。厚度约为0.5nm的氮化物对蚀刻模式氧化具有很强的免疫力，导致Si柱形成。随着氧化时间的延长，膜层高度线性增加.氮化物也可以作为氧化掩模，通过将样品从真空中取出到空气中进行真空氧化。这一结果表明，所提出的工艺在柱和点的形成中是有用且有效的。3.在600- 650 ℃的较低温度范围内氮化，得到了与SiN核尺寸和密度相对应的纳米级结构。下一步，将该工艺应用于SOI衬底上，制备Si点阵，这一工作正在研究中。

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.