Flow field investigation in a rotating disk chemical vapor deposition chamber with a perforated showerhead

Abstract

A flow field in a simulated rotating disk chemical vapor deposition chamber in which the inflow gases entered through a showerhead inlet was experimentally investigated using particle image velocimetry. The deposition uniformity was highly related to the flow pattern, which was influenced by the buoyancy, centrifugal, and flow inertia forces. This study investigated flow patterns for different processing parameters, namely chamber heights (20 and 40 mm), jet-to-disk temperature differences (0-500 degrees C), and disk rotational speeds (0-500 rpm). The time-averaged axial and radial velocity profiles were determined for examining the effects of rotation and heating on flow uniformity above the rotating disk. The Reynolds stress and turbulence intensity was found to be influenced by the buoyancy and rotation induced flow. At a high jet-to-disk temperature difference, the upward buoyancy force lifted the flow and prevented the inlet flow from reaching the disk surface. The buoyancy-induced flow can be suppressed through disk rotation or chamber height reduction. Moreover, the nondimensional parameters (Grashof number and rotational Reynolds number) can be used to construct flow regime maps and quantify the effects of rotation and heating even with the contribution from different chamber heights, disk temperatures, and rotational speeds. (C) 2017 Elsevier Inc. All rights reserved.