Analysis of Reactor Design on Interface Abruptness in Epitaxial Layers Grown by Organometallic Chemical Vapor Deposition

摘要

Interface abruptness of AlGaAs-GaAs layers was investigated for structures deposited in three OMCVD reactors with different geometries. Initial experiments were used to demonstrate the ability of each of the reactors to deposit layers with interfaces on the order of 3 atomic layers or less. Interfaces were viewed using high-resolution phase-contrast transmission electron microscopy. A geometry-based growth model was applied to the different reactors and one of the experimental interface formations was simulated in a time-dependent mode. To demonstrate the feasibility of the OMCVD growth of a device structure requiring abrupt interfaces, a high-electron-mobility transistor (HEMT) structure was deposited in one reactor and the presence of a two-dimensional electron gas was confirmed by Hall Effect measurements. Initial results indicate that OMCVD could be a viable approach for producing HEMT and other abrupt-interface structures, but, for high performance, the interface structures may require abruptness better than 2 or 3 atomic layers.