Effect of growth parameters on surface morphology evolution of MOMBE-grown InN

This work reports on the effects of growth temperature, TMIn flow rate and AlN buffer on InN thin films grown by RF-MOMBE epitaxy system. Structural and surface morphology were analyzed by XRD, FE-SEM, AFM and TEM, respectively. Electrical properties were performed by Hall measurement. While the growth temperature is at 500°C, InN grown directly on sapphire substrate preferred two-dimensional (2D) rather than island (3D) growth. However, the thickness of InN with smooth surface was limited at 50 nm due to residual stress caused by lattice mismatch. Moreover, In segregation was found under high TMIn flow rate condition. With the assistance of low-temperature grown intermediate AlN buffer layer, we can effectively improve the structural and electrical properties of InN. Experimental results indicate that the growth parameters are essential for engineering the growth of indium nitride.