Thermal aspects of LPCVD reactors with constant temperature heating zones

Low pressure chemical vapour deposition (LPCVD) reactors with constant temperature heating zones are examined for their capability to deliver desired temperature profiles for axial film thickness uniformity in nonepitaxial growth. A criterion is developed to estimate the approximate position in the reactor downstream of which thermal uniformity is likely. This is derived from an analytical solution of a model energy balance for the flowing fluid in the reactor, using assumptions, all of minor impact and all erring in a conservative way for the criterion. Three dimensionless parameters characterise the fluid and wafer temperature distributions. Guidelines for various operating modes are examined. 9 refs.