INSITU MONITORING OF GAN GROWTH USING INTERFERENCE EFFECTS

The interference effect was observed as an oscillation of the intensity of the transmitted IR radiation through the epitaxial film from the carbon susceptor during GaN growth using an IR radiation thermometer in metalorganic chemical vapor deposition (MOCVD). The IR radiation transmission intensity (IR-RTI) oscillations in GaN growth with and without an AlN buffer layer were studied in detail. The amplitude of the oscillation decreased with increasing thickness due to the thickness fluctuation of the growing GaN film within the measured spot area. In GaN growth with the AlN buffer layer, a very strong oscillation was observed because the surface morphology was much improved by the prior deposition of the AlN buffer layer. The sharp drop of the IR-RTI, which was attributed to the generation of the island growth of GaN around the nucleation site of the AlN buffer layer, was observed at a thickness of about 0.3-mu-m.