Uniformity control of group-III nitrides grown on 5 x 3 inch Al2O3 substrates in Planetary Reactors((R))

We report on recent results obtained using an AIX 2400G3HT production-type Planetary Reactor(R) in the 5 x 3 inch configuration for growth of typical group-III nitride layer structures consisting of GaN, InGaN and AlGaN. The optimum reactor geometry has been found by extensive modeling of the reacto r design. Increased thermal management allows maximum reactor temperatures above 1400 degreesC. As a consequence of extensive reactor modeling, the pr ocess transfer from 6 x 2 to 5 x 3 inch configuration was carried out by si mple scaling of the corresponding process parameters of the 6 x 2 inch conf iguration. The scaling factor is calculated with respect to the changed rea ctor geometry. We used optical reflectrometry for in-situ growth control du ring this process development and could confirm the theoretical scaling req uirements for obtaining identical growth conditions as compared to the 6 x 2 inch reactor configuration. This is verified by the generation of identic al reflectance spectrum features. This important issue of in-situ control i s discussed in detail. The TMGa efficiency could be kept at about 17%. Swit ching to the 8 x 3 inch configuration, the efficiency increases up to about 27%, which is an improvement of 63% as compared to the 6 x 2 inch configur ation. (C) 2000 Elsevier Science B.V. All rights reserved.