Dry Chemical Etching of Gallium Arsenide in OMVPE Reactors

砷化镓（GaAs）的外延生长， 有机金属气相外延（OMVPE）已用于 生长各种III-V族和II-VI族化合物半导体， 电子和光电器件。 优化反应器 OMVPE生长的设计已经通过例如气流 可视化和数值模拟。 的主要优点 分子束外延（MBE）的优点是， 前者的速率可以比MBE高4 - 10倍， 使电子设备的生产成为可能， 体积大。 OMVPE的吞吐量和产量在大- 如果在原位完成， 器件处理，例如蚀刻、图案化和再生长 被证明了。 这种处理的优点是： (1)制造低损耗埋地 波导和低阈值掩埋二极管激光器 (2)简化处理 (3)低污染 因此，PI正在开发接口， 简单的干法蚀刻工艺， 无污染物引入或表面的大面积蚀刻 降解 在这项研究中，他们计划调查原位干燥 使用甲基自由基的GaAs和AlGaAs的化学蚀刻 源 PI计划研究“反向增长”或 用几种甲基自由基源在近室温下对GaAs的“腐蚀” OMVPE生长中典型的大气压。 这些研究 将确定最有前途的来源和经营 OMPVE反应器中GaAs的原位腐蚀条件 而没有杂质积累和/或表面形态变化。 偶氮甲烷、碘甲烷、碘化氢和三甲基 砷将作为源化合物在温度 在300- 600 oC的范围内。 另一个目的是研究 蚀刻的取向依赖性。 图案化基板 将研究暴露的不同晶体取向。 蚀刻的各向异性也将用掩蔽的 衬底 此外，这项工作的目的是确定 条件和理解导致“贫穷”的过程 蚀刻制度，如由衬底形态或 改变或掺入杂质。

The epitaxial growth of gallium arsenide (GaAs) by organometallic vapor phase epitaxy (OMVPE) has been used to grow various III-V and II-VI compound semiconductors and for electronic and optoelectronic devices. Optimizing the reactor design for OMVPE growth has been done by, for example gas flow visualization and numerical simulation. A major advantage of OMVPE over molecular beam epitaxy (MBE) is that the growth rates of the former can be four to ten times higher than MBE, making feasible the production of electronic devices on a large volume scale. The OMVPE throughput and yield in large- scale device fabrication could be enhanced if complete in-situ device processing, such as etching, patterning and regrowth were demonstrated. The advantage of such processing are: (1) potential for fabrication of low-loss buried waveguides and low threshold buried diode lasers (2) simplified processing (3) low contamination The PIs are therefore working at interfaces developing a simple dry etching process with capabilities for in-situ, large area etching without contaminant introduction or surface degradation. In this study, they plan to investigate the in-situ dry chemical etching of GaAs and AlGaAs using methyl radical sources. The PIs plan to study the "reverse growth" or "etching" of GaAs using several methyl radical-sources at near atmospheric pressure typical in OMVPE growth. These studies will identify the most promising source and operating conditions for the in-situ etching of GaAs in OMPVE reactors without impurity buildup and/or surface morphology changes. Azomethane, iodomethane, hydrogen iodide, and trimethyl arsenic will be examined as source compounds at temperatures in the range of 300-600oC. Another objective is to examine the orientation dependence of etching. Patterned substrate with different crystal orientations exposed will be studied. The anisotrophy of etching will also be examined with masked substrate. Additionally, the work aims at identifying the conditions and understanding the process leading to "poor" etching regimes as evidenced by either substrate morphology changes or the incorporation of impurities.