COMPARISON OF HYDROGEN AND NITROGEN AS CARRIER GAS FOR MOVPE GROWTH OF GAN

We investigated the effect of the carrier gas on GaN single layers gro wn in an AIX 200 RF horizontal flow low pressure MOVPE system. On simi larly processed c-plane sapphire substrates (with regard to preparatio n and nucleation) GaN single layers were grown both under N-2 and H-2. Various measurement methods were applied to assess the layer quality. While some characteristics of layers grown in both N2 or H-2 atmosphe res are promising, both processes show inherent deficiencies that will have to be addressed for device quality epitaxy. For GaN single layer s grown in N-2 ambient bad morphology and poor electrical data were fo und. Layers grown with H-2 as carrier gas suffer from a strong yellow band emission in low excitation photoluminescence measurements and dis advantages from the large scale device production point of view, such as higher loss of material to the reactor walls. (C) 1998 Elsevier Sci ence B.V. All rights reserved.