Research Initiation Award: Chemical Kinetics and Transport Phenomena of GaAs Growth by MOCVD Using Alternative Arsenic Precursors

金属有机化学气相沉积（MOCVD）是一种多用途的 沉积微电子材料的技术 制造，包括金属，半导体和绝缘体， 使用多种有机金属前体。 在一个典型 热解MOCVD工艺，反应气体的混合物， 注射到加热的固体基底和薄固体膜上 已经存了 MOCVD是一种很有前途的沉积技术， III-V族和IIV族的薄外延层和异质结构 化合物半导体如GaAs，AlGaAs，InP，InGaAs， InGaAsP、ZnSe、HgCdTe等。 限制了MOCVD用于生长薄 化合物半导体和人造薄膜 微结构（超晶格、量子威尔斯和原子结构） 突变的组成和掺杂界面）是：（1）缺乏 了解下伏气相和地表 （2）缺乏对反应的理解， 化学动力学和复杂的运输现象， 决定了生长和组成的均匀性， 材料，以及（3）高毒性引起的安全问题 通常使用的前体气体，特别是V族气体 氢化砷化氢和磷化氢。 本研究的目的是：（a）研究 替代（安全）砷的分解动力学 前体（三甲基胂、叔丁基胂）和 常见的有机金属前体（三甲基-和三乙基- 镓和铝）用于GaAs和AlxGa 1-xAs的MOCVD; (b)发展GaAs生长的反应输运模型， 能够预测观察到的替代砷前体 生长和碳掺入率;（c）生长GaAs 从上述前体外延层，并研究其 特性. 前体的分解将是 在逆流扩散反应器中进行， 均匀的反应速率和热壁管式反应器 以获得整体的价格。 这项研究的最终目的是 是开发有效扩大MOCVD的程序， 由GaAs沉积薄外延层的方法 更安全的前体气体和受控的均匀性， 组成和形态。

Metalorganic chemical vapor deposition (MOCVD) is a versatile technique for depositing materials for microelectronics fabrication, including metals, semiconductors, and insulators, using a variety of organometallic precursors. In a typical pyrolytic MOCVD process, a mixture of reactive gases is injected over a heated solid substrate and a thin solid film is deposited. MOCVD is a promising technique for depositing thin epitaxial layers and heterostructures of III-V and IIV compound semi-conductors such as GaAs, AlGaAs, InP, InGaAs, InGaAsP, ZnSe, HgCdTe, etc. The problems that are currently limiting commercial applications of MOCVD for growing thin films of compound semi-conductors and artificial microstructures (superlattices, quantum wells, and atomically abrupt compositional and doping interfaces) are:(1) lack of understanding of the underlying gas-phase and surface reactions, (2) lack of understanding of the coupling between chemical kinetics and complex transport phenomena that determines the growth and compositional uniformity of the material, and (3) safety issues arising from the high toxicity of commonly used precursor gases, especially of the group-V hydrides arsine and phosphine. The objectives of this research is: (a) to study the decomposition kinetics of alternative (safer) arsenic precursors (trimethyl-arsine, tertiary-butyl-arsine) and common organo-metallic precursors (trimethyl- and triethyl- gallium and aluminum) used in MOCVD of GaAs and AlxGa1-xAs; (b) to develop reaction-transport models of GaAs growth from alternative arsenic precursors capable of predicting observed growth and carbon incorporation rates; (c) to grow GaAs epitaxial layers from the above precursors and study their properties. The decomposition of the precursors will be performed in a counterflow diffusion reactor to obtain purely homogeneous reaction rates and in a hot-wall tubular reactor to obtain overall rates. The ultimate goal of this research is to develop procedures for efficient scale-up of the MOCVD process for depositing thin epitaxial layers of GaAs from safer precursor gases and with controlled uniformity, composition, and morphology.