Surface chemistry of hydrogen on Si surfaces

Si 表面氢的表面化学

基本信息

批准号：
09450015
负责人：
SUEMITSU Maki
金额：
$ 9.02万
依托单位：
TOHOKU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09450015/
关键词：
silicon epitaxy CVD gas-source MBE doping hydrogen desorption silicon carbide silane disilane シリコンホスフィン水素酸化過程アセチレンガスソース MBE 吸着脱離

项目摘要

With an aim of clarifying the growth mechanism of Si epitaxy on atomic/molecular basis, we have achieved the following.1. We found that, in Si-GSMBE, source-gas molecules adsorb onto the Si surface using two sites at low temperatures and four sites at high temperatures. The mechanism that determines the growth-rate activation energy at low temperatures was also clarified.2. It was clarified for the first time that hydrogen desorption from Si(100) surface can take a reaction order that is larger than unity, as opposed to previous understandings. The reaction order depends on the choice of the hydrogenating gas and the thermal history, whose variation is unifiedly accounted for by using a concentration of paired hydrogen atoms on the surface.3. Concerning the surface chemistry during in-situ doping process, we first developed a novel method for controlling the surface coverage of phosphorus atoms, in which we simply count the number of adsorption/desorption sequence. Using the method, the role of surface P atoms on Si epitaxy was found to be suppression of the adsorption process and suppression of the hydrogen desorption. More precisely, the latter effect consists of two channels : increase of the activation energy and the increase of the reaction order. These findings provide basis for understanding the growth-rate retardation during phosphorus doping.4. To achieve good SiC heteroepitaxy on Si, we compared the atomic arrangements of acetylene- and monomethylsilane(MMS)-adsorbed Si surfaces. On acetylene-adsorbed surface, there occurs site exchange between surface carbon and substrate Si atoms, while the exchange is drastically suppressed on MMS-adsorbed surface. By using MMS, then, a qualified crystalline film of SiC was successfully obtained on Si(100), at as low as 900C without any carbonization procedures. It was clarified that complete elimination of surface hydrogen is key to the qualified epitaxy of SiC.

为了在原子/分子基础上阐明SI外延的生长机制，我们已经达到了以下内容。1。我们发现，在Si-GSMBE中，使用两个位点在低温下和高温下的四个位点吸附到Si表面上。还阐明了确定低温下生长速率活化能的机制。2。首次澄清的是，与以前的理解相比，从Si（100）表面氢解吸可以采用大于统一的反应顺序。反应顺序取决于氢气气体和热历史的选择，其变异是通过在表面上使用成对的氢原子浓度来统一解释的。3。关于在原位掺杂过程中的表面化学，我们首先开发了一种用于控制磷原子表面覆盖的新方法，在该方法中，我们只是在计算吸附/解吸序列的数量。使用该方法，发现表面P原子对Si外延的作用是抑制吸附过程和抑制氢解吸的。更确切地说，后一种效果由两个通道组成：激活能量的增加和反应顺序的增加。这些发现为理解磷掺杂过程中的生长速率延迟提供了基础。4。为了在SI上获得良好的SIC杂次，我们比较了乙炔和单甲基硅烷（MMS）吸附的Si表面的原子布置。在乙炔吸附的表面上，在表面碳和底物Si原子之间发生位点交换，而交换在MMS添加的表面上被大大抑制。然后，通过使用MMS，在SI（100）上成功获得了合格的SIC的结晶膜，低至900C，而没有任何碳化程序。可以澄清的是，完全消除表面氢是SIC的合格外观的关键。