Modeling of a two stage RF plasma reactor for SiC deposition

Summary form only given. Chemical vapor deposition (CVD) is often used for the growth of Silicon Carbide (SiC) films. The precursor gases, silane and methane, flow through a quartz tube at atmospheric pressure with a graphite susceptor located downstream of the inter. The conventional method for growing SiC films is to heat the susceptor by low frequency (kHz) RF which in turn heats the gas by thermal transfer up to several thousand K and forms reactive species near the growth substrate. The high temperature and pressure of the gas is thought to be one cause of film defects such as micropipes. An alternative approach, plasma-enhanced CVD, can be applied wherein, an upstream plasma forms reactive species in non-equilibrium conditions. The neutral gas temperature and pressure may then be substantially reduced, while defects are reduced as long as the destructive effects of ion bombardment are limited. The present research focuses on the design of a two stage RF reactor in which a high frequency RF (MHz) antenna is added upstream of the substrate to form the plasma. We have developed a 1-D flow code to investigate various design options for the reactor. The model includes electromagnetic coupling, electron heating and plasma chemistry involving silane and methane reactions. 37 species and 183 reactions are considered. The model addresses kinetic and transport properties which occur in the gas phase and can be used to predict the axial profiles of the electron and gas temperature, neutral and charged species and particle and energy fluxes. We report on the impact of the design parameters: input power, gas pressure, RF frequency, flow rate, and tube dimensions.