MOVPE of GaN on sapphire using the alternate precursor 1,1-dimethylhydrazine

To date, the most successful method to grow device-quality GaN epitaxial layers by metal-organic vapor-phase epitaxy (MOVPE) uses trimethyl (or triethyl) gallium (Me3Ga/Et-3 Ga) for the Ga source and ammonia (NH3) for the N source. It is a high-temperature process with deposition temperatures typically in excess of 1000 degreesC due to the high stability of the ammonia molecule. The use of a nitrogen precursor that decomposes at lower temperature is expected to result in a more efficient process and to allow growth of alloys at a lower temperature. The liquid precursor 1,1-dimethylhydrazine (Me-2 NNH2) has been tested as such an alternative precursor. GaN epilayers have been grown successfully on c-plane sapphire using low V/III ratio. The growth parameters and the characteristics of the grown epilayers are presented. (C) 2000 Elsevier Science B.V. All rights reserved.