Fort Monmouth-University of Massachusetts: Mechanistic Studies of MOCVD Growth

我们的研究重点是研究金属有机化合物蒸气生长III-V半导体时发生的表面反应。证词，MOCVD。目前已经提出了许多MOCVD的动力学和力学模型，其中包含了大量的反应步骤和动力学参数。然而，很少有人研究III-V半导体生长过程中表面发生的反应。原位技术可用于表征表面反应，但它们通常仅限于研究温度和压力低于用于MOCVD生长的那些(1℃和500℃)。最值得注意的是，透射式和反射式红外光谱学与同位素标记相结合，彻底改变了我们的理解固体表面的催化反应。随着温度的升高，半导体在红外线不再是透明的，无法使用传输技术；事实上，这些固体开始发出辐射。幸运的是，发射的辐射的光谱可以用类似的技术来分析，并且包含关于被吸附的中间体。因此，发射光谱可能是确定半导体上高温反应的这些活性物种的有效工具曲面。我们建议使用红外发射光谱结合同位素示踪和在线质谱学来研究表面物种。在吸附和反应过程中，并显示不同的前体如何影响表面组成。在平行传输中，将在蒙茅斯堡对相同样品进行红外线和详细的表面分析。这种独特的互补技术组合将被用来更好地确定II-V半导体表面生长的表面反应模型。

The focus of our proposed research is to investigate the surface reactions occurring during the growth of III-V semiconductors by metal organic chemical vapor deposition, MOCVD. Many kinetic and mechanistic models for MOCVD have been proposed that include numerous reactions steps and kinetic parameters. However, few studies have been conducted to study the reactions occurring at the surface during the growth of III-V semiconductors. In situ techniques are available to characterize surface reactions but they are normally limited to study lower temperatures and pressures than those employed in MOCVD growth (to 1Atm.and500oC). Most notably, transmission and reflectance infrared spectroscopy in conjunction with isotopic labelling has revolutionized our understanding of catalytic reaction on solid surfaces. As temperature increases, semiconductors are no longer transparent in the infrared and transmission techniques can not be employed; indeed, these solids begin to emit radiation. Fortunately, the spectra of the emitted radiation can be analyzed by similar techniques and contains similar information with regard to the adsorbed intermediates. Thus, emission spectroscopy may be an effective tool for determining these reactive species for higher temperature reactions on semiconducting surfaces. We propose to use infrared emission spectroscopy in conjunction with isotopic tracers and on-line mass spectroscopy to investigate the surface species during the adsorption and reaction and to show how different precursors effect surface compositions. In parallel transmission infrared and detailed surface analyses for the same samples will be conducted at Fort Monmouth. This unique combination of complementary techniques will then be used to better determine surface reaction models for growth of II-V semiconductor surfaces.