Plasma Deposition and Modeling of Thin-Film, High-Bandgap Nitrides

Plasma dynamics and plasma-surface interactions are central to many thin film deposition processes, but in spite of their importance, are not well understood theoretically or empirically. There has been even less study of the plasma deposition physics of the high-bandgap nitrides GaN, AlN, InN, and their alloys, which are becoming increasingly important in electronic applications. Spire proposes to study thin-film nitride deposition from an electron cyclotron resonance (ECR) driven plasma; plasma modeling will be performed by Process Analysts, Inc (PAI). In Phase I, Spire's ECR plasma reactor, which ha already demonstrated thin film deposition of InxGa1-xN alloys, will be instrumented with plasma diagnostics, and a series of nitride depositions will be conducted using metalorganic (MO) sources of the Group III metals and nitrogen. PAI will modify an existing finite-element model of plasma enhanced chemical vapor deposition (PECVD) to account for ECR plasma heating, magnetic anisotropy, and MO sources. The deposition model will predict the effects of plasma parameter changes on thin-film deposition. Good Phase I results would lead to Phase II in which refined plasma diagnostics will be installed and operated on the ECR plasma reactor to gain in-depth understanding of volume and surface processes during plasma deposition. Plasma modeling will be extended to include effects of non-uniform plasma heating, magnetic field effects on transport, and more complete cross-sections to better model the plasma chemistry. Phase III will see early commercialization of nitride deposition service and reactor sales by Spire, and sales by PAI of software predicting deposition parameters; this software could be made part of a feedback control system for the ECR plasma reactor to assure uniform, reproducible, thin-film deposition in a production setting.