氮化衬底对MOCVD生长GaN的影响

采用MOCVD生长技术以Al2O3为衬底对GaN生长进行了研究．用霍尔测量技术、光致发光技术以及光学显微镜测量了GaN的电学性能、光学性能以及表面形貌．研究表明，GaN低温缓冲层生长之前的氮化衬底工艺对GaN外延层表面形貌、发光性能、电学性能有显著影响．合适的氮化衬底条件可得到表面形貌、发光性能和电学性能均较好的GaN外延膜．研究表明长时间氮化衬底使GaN外延膜表面粗糙的原因可能是由于氮化衬底影响了后续高温GaN的生长模式，促使GaN三维生长所导致的．

INFLUENCE OF NITRIDATION TO THE CHARACTERISTICS OF GaN GROWN BY MOCVD

The growth of GaN was performed by a Thomas Swan MOCVD on (0001) oriented sapphires. Properties of GaN layers were investigated by photoluminescence, Hall measurement, and optical microscope, respectively. The results indicated that the nitridation condition obviously influenced the photoluminescence properties and electric parameters of GaN films. The GaN films photoluminescence properties could be improved and the background carrier concentrations could be reduced if the nitridation condition was proper. The long nitridation time would influenced the GaN growth mode and promote the 3D growth of GaN, which results in rough surface morphology.