HIGH-QUALITY GAN GROWN BY MOVPE

Several nitrogen precursors have been used for the growth of GaN in MO VPE, but so far the best results were obtained using NH3, even though NH3 does not produce a significant amount of active species at the gro wing interface. To produce active species from N-2 or NH3, a remote pl asma-enhanced chemical vapour deposition (RPECVD) process has been imp lemented. In addition, nitrogen metalorganic precursors, triethylamine and t-butylamine, were also used. To accurately control the critical parameters of the MOVPE of GaN, we have implemented a laser reflectome try equipment, which allows a real-time in situ monitoring of the diff erent steps of the growth, i.e. nitridation of the substrate, nucleati on, heat treatment, and deposition. Using an appropriate buffer layer, GaN grown on sapphire using NH3 as nitrogen precursor, shows sharp lo w temperature photoluminescence lines (4 meV at 9 K), whereas other ni trogen precursors did not lead to comparable electronic quality.