Numerical Study of Mixed Convection Flow in an Impinging Jet CVD Reactor for Atmospheric Pressure Deposition of Thin Films

Abstract

A systematic numerical study has been conducted of the mixed convection flow in a novel impinging jet chemical vapor deposition (CVD) reactor for deposition of thin films at atmospheric pressure. The geometry resembles that of a pancake reactor but the inflow gases enter through a small nozzle to provide high inlet momentum. A finite-volume-based computational procedure is used to integrate the governing flow, energy, and scalar transport equations with high accuracy. The effects of the temperature dependent properties are fully accounted for. The effects of operating pressure, wafer rotation rate, and inlet flow rate of the carrier gas are investigated. The main benefit of the new geometry is the suppression of the buoyancy-driven flow even at atmospheric pressures due to the lower mixed convection parameter. We show that the new geometry can produce thin films of high radial uniformity and also with high growth rate. Comparisons are also made with a conventional stagnation flow reactor for which it is shown that beyond a moderate pressure (∼0.1 atm), the flow is dominated by natural convection, and the reactor is unsuitable for practical use.