ATOMIC-FORCE MICROSCOPY GROWTH MODELING OF SIC BUFFER LAYERS ON SI(100) AND QUALITY OPTIMIZATION

The effect of various growth conditions has been studied in order to m odelize and optimize the SiC buffer layers obtained by reactive chemic al-vapor deposition (RCVD) on Si(100) substrates. First, thermodynamic calculations have been carried out on the Si-H-2-CxHyClz system to si mulate the RCVD process and to foresee the nature and the evolution of the deposit with varying parameters. The experiments have confirmed s ome of the thermodynamic results, such as the carbon deposition in spe cific conditions, and brought out complementary information on the kin etics point of view. Due to our low heating up rate, no SiC island for mation was characterized at the early stage of growth. The obtained Si C layers are ultrathin with a very particular morphology. We propose a new model of growth based on atomic force microscopy observations to explain the resulting morphology. The optimal conditions have been ded uced to elaborate ultrathin, smooth, and monocrystalline beta-SiC buff er layers. (C) 1996 American Institute of Physics.