A STUDY OF THE GROWTH-KINETICS OF II-VI METALORGANIC VAPOR-PHASE EPITAXY USING IN-SITU LASER REFLECTOMETRY

A new kinetic model for II-VI telluride metalorganic vapour phase epit axy (MOVPE) is proposed based on new experimental results obtained by in situ reflectometry. New observations include the decrease in growth rate at higher temperature, dependent on the type of tellurium organo metallic and VI/II ratio, and the dependence of activation energy on V I/II ratio at low temperatures. The activation energy in the low tempe rature regime, normally referred to as the kinetic regime, is smaller than for the equivalent vapour phase pyrolysis for dimethyltelluride ( DMTe) and di-isopropyltelluride (DIPTe), with values as small as 14.2 kcal/mol for CdTe from DIPTe with a VI/II ratio of 1. The DIPTe concen tration for HgTe growth was a factor of six higher than for CdTe growt h to achieve the same growth rates. The proposed model explains both t he low and high temperature regimes with excellent fit to the data. Th e low temperature growth regime is limited by surface catalysis of tel lurium organometallics bonded to group II surface atoms and the high t emperature is tellurium organometallic desorption limited.