Investigation of the wafer temperature uniformity in an OMVPE vertical rotating disk reactor

Measuring the wafer temperature uniformity is one of most difficult problems in the development of organometallic vapor phase epitaxy (OMVPE) equipment. Until recently, the lack of a good experimental technique limited the understanding of OMVPE rotating disk reactor (RDR) thermal dynamic. We have developed a rotating wafer thermal imaging technique, which for the first time allows a real-time experimental investigation of the temperature distribution across the wafer in an RDR under realistic deposition conditions. This technique allows investigation on how process parameters such as the growth temperature (from 650 to 800°C), reactor pressure (from 10 to 620 Torr), reactant flow (from 2 to 30 slm), and wafer carrier rotation speed (from 300 to 1030 rpm) affect the wafer temperature uniformity. This information has allowed us to establish under which conditions single or multi-zone heating should be used in the OMVPE reactor. A wafer temperature uniformity of better than 1°C was demonstrated for both an optimized single zone heating system under a selected combination of process parameters, and for a two-zone heating system over a wide range of the process parameters.