Effect of growth rate on morphology evolution of 4H-SiC thick homoepitaxial layers

In this paper, the surface morphologies of 4H-SiC epilayers with different growth rates were investigated by Candela CS920, atomic force microscope and optical microscope. The investigation of the surface morphologies of the samples showed that an evolution from micro-step to small-step and then back to macro-step occurred on the surface, with the surface roughness increased gradually during this evaluation. It was concluded that the higher growth rate the larger differences of step migration rate. In this case, the steps easily gather together forming greater steps. The gathering effect was enhanced with the increase of the growth rate.