(658b) Generalized Design Criteria for Vertical Chemical Vapor Deposition Reactors

A very common reactor configuration in the microelectronics industry is the vertical chemical vapor deposition reactor with a rotating susceptor. In such a reactor the gaseous stream carrying the film precursors flows down towards a heated rotating susceptor where the substrates to be coated are placed. Typical design objectives for such reactors include the elimination of buoyancy- and inertia-driven flow recirculations, control of thickness and compositional uniformity in the deposited films, and the ability to grow abrupt heterojunctions. The detailed analysis of such reactors using fundamental models of the transport phenomena and chemical kinetics poses a variety of challenges [1], but also offers the possibility for developing generalized maps of their parameter space identifying regions in which specific design criteria are met [2].

This presentation will focus on a detailed parametric study of vertical chemical vapor deposition reactors addressing the following issues: (1) The development of generalized design criteria for the elimination of flow recirculations based on the inlet Reynolds number, the rotational Reynolds number, the aspect ratio (inlet to susceptor distance divided by susceptor diameter) and the Grashof number. (2) The development of generalized criteria for thickness and compositional uniformity of the deposited films based on Peclet and Damkoehler numbers for conditions that satisfy the criteria developed in part (1). Applications of this approach to the design of reactors used for growing multilayer structures of compound semiconductors such as GaAs, (Al,Ga)As, GaN and (Al,Ga)N will be discussed and compared to available experimental data. The ultimate objective is to develop a methodology for optimal design of such reactors that does not depend heavily on experimental trial and error.

References

1. C. Theodoropoulos, T.J. Mountziaris, H.K. Moffat and J. Han, "Design of Gas Inlets for the Growth of Gallium Nitride Films by Metalorganic Vapor Phase Epitaxy", Journal of Crystal Growth , 217, 65-81 (2000).

2. R.P. Pawlowski, C. Theodoropoulos, A.G. Salinger, T.J. Mountziaris, H.K. Moffat, J.N. Shadid and E.J. Thrush, "Fundamental Models of the Metalorganic Vapor Phase Epitaxy of Gallium Nitride and Their Use in Reactor Design", Journal of Crystal Growth, 221, 622-628 (2000).