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1、硅热氧化工艺余明刚 唐波 张芊 硅热氧化工艺硅热氧化工艺 硅(Si)与含有氧化物质的气体，例如水汽 和氧气在高温下进行化学反应，而在硅 片表面产生一层致密的二氧化硅(SiO2)薄 膜。这是硅平面技术中一项重要的工 艺。常用的热氧化装置（图1）将硅片置 于用石英玻璃制成的反应管中，反应管 用电阻丝加热炉加热一定温度(常用的温 度为9001200，在特殊条件下可降到 600以下)，氧气或水汽通过反应管（ 典型的气流速度为1厘米/秒）时，在硅片 表面发生化学反应 生成SiO2层，其厚度一般在几十埃到上 万埃之间。Silicon (Si) and contains oxide qualitative
2、gases, such as water and oxygen for chemical reaction under high temperature, and in silicon wafer surface produces a layer of density of silica (SiO2) film. This is an important silicon flat technology process. The commonly used thermal oxidation device (figure 1) will be in use silicon quartz glas
3、s tube made in response, reaction furnace heating must work resistance wire temperature (commonly used temperature of 900 1200 , under special conditions can drop to 600 below), oxygen or water vapour through the reaction tube (typical flow speed of 1 cm/SEC), silicon wafer surface in produces chemi
4、cal reaction Generate SiO2 layer, the thickness of the generals dozens to tens of thousands between Evans. Si(固态)+O2(气态)SiO2(固态) 或 Si(固态)+2H2O(汽态)SiO2(固态 )+2H2(气态) 硅热氧化工艺，按所用的氧化气氛 可分为：干氧氧化、水汽氧化和湿 氧氧化。干氧氧化是以干燥纯净的 氧气作为氧化气氛，在高温下氧直 接与硅反应生成二氧化硅。水汽氧 化是以高纯水蒸汽为氧化气氛，由 硅片表面的硅原子和水分子反应生 成二氧化硅。水汽氧化的氧化速率 比干氧氧化的为大
5、。而湿氧氧化实 质上是干氧氧化和水汽氧化的混合 ，氧化速率介于二者之间。Silicon thermal oxidation technology, used by the oxidation atmosphere can be divided into: dry oxygen oxidation, water vapor oxidation and the wet oxidation of oxygen. Dry oxygen oxidation is pure oxygen as dry oxidation atmosphere, under high temperature to oxyg
6、en reacts directly with silicon silica. Steam oxidation is high purity steam oxidation atmosphere for, the silicon wafer surface silicon atom and a water molecule reaction generated silica. The oxidation of the water vapor oxidation rate than dry oxygen oxidation of great. And wet oxidation is essen
7、tially dry oxygen oxygenation and water vapor oxidation of mixed, oxidation rate between between the two. 在集成电路工艺中，以加热高纯 水作为水蒸汽源，而湿氧氧化则 用干燥氧气通过加热的水（常用 水温为95）所形成的氧和水汽混 合物形成氧化气氛。用高纯氢气 和氧气在石英反应管进口处直接 合成水蒸汽的方法进行水汽氧化 时，通过改变氢气和氧气的比例 ，可以调节水蒸汽压，减少沾污 ，有助于提高热生长二氧化硅的 质量。In the integrated circuit technology, hi
8、gh pure water as steam heating source, and with dry wet oxidation is oxygen oxygen through the heating water (commonly used water temperature for 95) by the formation of the oxygen and water vapor mixture formation oxidation atmosphere. With high purity hydrogen and oxygen in quartz tube inlet react
9、ion direct synthesis methods of water vapour water vapor oxidation, by changing the ratio of hydrogen and oxygen, can regulate steam pressure, reduce contamination, help to improve the quality of the silica thermal growth.对硅热氧化动力学的研究表 明，除了几个分子层外，硅热 氧化是由氧或水分子H2O（或 OH-）扩散通过已形成的二氧 化硅层,在Si-SiO2界面与Si反 应而
10、生成二氧化硅。随着氧化 过程的进行，Si-SiO2界面不断 向硅内部推移。当硅生成为二 氧化硅时,体积增大2.2倍。The dynamics of thermal oxidation of silicon study show that, except a few molecular layer outside, silicon of thermal oxidation by oxygen or is water molecules H2O (or OH-diffusion through the silica has formed layer in Si-SiO2 interface and
11、 Si reaction and the generated silica. Along with the oxidation process, Si-SiO2 interface to keep the silicon internal goes on. When silicon born become silica, 2.2 times the increase in size. 二氧化硅的生成速率主要由两 个因素控制:在Si-SiO2界面 上硅与氧化物反应生成二氧化 硅的速率;反应物(O2、H2O 或OH-)通过已生成的二氧化硅 层的扩散速率。按照硅热氧化 动力学，反应过程可用下式表 示
12、：The generation of silica rate mainly by the two factors control: (1) in Si-SiO2 interface silicon oxide reacts with the rate of silica; (2) the reactant (O2, H2O or OH-through the already generated silica layer rate of expansion. According to the silicon of thermal oxidation dynamics, the reaction
13、process can be used under type says: Type of for the generated silica x0 thickness; T for oxidation of time; A, B and and oxidation atmosphere and the other is the constant oxidation conditions. X0Ax0B(t+) 式中x0为生成的二氧化硅厚 度;t为氧化时间；A、B和 是与氧化气氛和其他氧化条 件有关的常数。当氧化时间很短、生成的二氧 化硅很薄时,氧化速率主要由 硅和氧化物质的反应速率控 制。这时上
14、式可简化为x0 (B/A)(t+),即氧化层厚度与氧 化时间呈线性关系。B/A 称为 线性速率常数,与硅片晶向密 切相关。通常以(111)晶向时的 B/A为最大,(100)晶向时的B/A 为最小, B/A(111)/B/A(100)1.68；When time is short, the oxidation of the generation of silica is very thin, oxidation rate mainly by the silicon oxide and the reaction rate control. At this time of the simplifie
15、d as x0 = (B/A) (t + ), namely oxidation layer thickness and oxidation time in A linear relationship. B/A called linear rate constant, and silicon wafer closely related. Usually in (111) wafer of B/A for A maximum, 100 () wafer of B/A is minimum, B/A (111) / B/A (100) 1.68; 当SiO2达到一定的厚度时, 氧化速率由氧化物质通
16、过已 生成的二氧化硅膜的扩散速 率所控制。这时，上式可简 化为x娿Bt，也就是厚度 与时间呈抛物线关系,B为抛 物线速率常数。B和B/A都 指数地依赖于氧化温度,B的 激活能分别约为1.24电子伏( 干氧)和0.78电子伏(水汽)， B/A的激活能约为2.0电子伏 （干氧和水汽）。When SiO2 to achieve a certain thickness, oxidation rate by oxidation material through the already generated silica film rate of expansion control. At this time, the model can be simplified to the x E = Bt, also is the thickness and
