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In microfabrication, thermal oxidation is a way to produce a thin layer of oxide (usually silicon dioxide) on the surface of a wafer. The technique forces an oxidizing agent to diffuse into the wafer at high temperature and react with it. The rate of oxide growth is often predicted by the Deal-Grove model. Thermal oxidation may be applied to different materials, but this article will only consider oxidation of silicon substrates to produce silicon dioxide. == The chemical reaction == Thermal oxidation of silicon is usually performed at a temperature between 800 and 1200°C, resulting in so called High Temperature Oxide layer (HTO). It may use either water vapor (usually UHP steam) or molecular oxygen as the oxidant; it is consequently called either ''wet'' or ''dry'' oxidation. The reaction is one of the following: : : The oxidizing ambient may also contain several percent of hydrochloric acid (HCl). The chlorine removes metal ions that may occur in the oxide. Thermal oxide incorporates silicon consumed from the substrate and oxygen supplied from the ambient. Thus, it grows both down into the wafer and up out of it. For every unit thickness of silicon consumed, 2.17 unit thicknesses of oxide will appear.〔http://www.eng.tau.ac.il/~yosish/courses/vlsi1/I-4-1-Oxidation.pdf〕 If a bare silicon surface is oxidized, 44% of the oxide thickness will lie below the original surface, and 56% above it. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Thermal oxidation」の詳細全文を読む スポンサード リンク
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