On the flow stability in vertical rotating disc MOCVD reactors under a wide range of process parameters

Abstract

A systematic study has been performed to investigate flow stability in vertical rotating disc MOCVD reactors under a wide range of process parameters, such as chamber pressure (10–1000 Torr), wafer carrier rotation rate (0–1500 rpm), growth temperature (500–1100 °C), isothermal reactor wall temperature (25–250 °C), total gas flow rate (10–350 slm), and varying concentrations of hydride and inert carrier gases (H 2, N 2, and NH 3). Quantitative flow stability maps have been developed based on extensive two-dimensional/three-dimensional numerical modeling for the entire domain of possible process parameters. It has been shown that all typical flow regime regions encountered in a rotating disc reactor (plug-flow, stagnation-flow, buoyancy-induced, and rotation-induced flow regimes) can be presented in a single “ P– ω ” (pressure vs. rotation rate) diagram, which also transparently captures the effects of all process parameters mentioned above on the flow stability in the rotating disc reactors. Two zones of buoyancy-driven flow with different asymptotic behavior for low and high rotation rate (weak and strong rotation dependence, respectively) have been identified. Moreover, a rotation rate range has been identified where transition between buoyancy-driven flow and rotationally driven flow occurs, which is also the range where the maximum pressure can be achieved in rotating disc reactors.