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

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 (H2, N2, and NH3). 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  –ωω” (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.