Two-step Growth of GaN Films Grown on Si (111) Substrate by Using SiC Intermediate Layer

Single crystalline hexagonal GaN films with AlN buffer layer were grown on Si(111) substrate using SiC intermediate layer by two-step growth method. In single-step growth, crystal quality and surface morphology were strongly depended on reactor pressure. Surface morphology was improved but crystal quality deteriorated at low pressure around 70 mbar. As reactor pressure increases to 100 mbar, crystal quality was improved but surface was rougher. From this result, we tried to grow GaN layer by two-step method to promote both crystal quality and surface morphology. Pressure is varied in the first-step growth form 70 mbar to 120 mbar. For the second-step growth the pressure was kept constant at 100 mbar. The pressure of first GaN epi-layer was optimized at 70 mbar. Crystal quality and Optical properties of GaN epi-layer strongly improved and crack density remarkably reduced by using two-step growth method. KCI Citation Count: 0