Deep UV excitation Raman spectroscopy of homoepitaxial 4H-SiC films grown by microwave plasma chemical vapor deposition

摘要

We have carried out homoepitaxial growth of 4H-SiC at relatively low temperature around 1050℃ by microwave plasma chemical vapor deposition (PCVD) for the purpose of providing more flexibility in the SiC device processing. In this study, we have characterized PCVD grown films by SEM and deep ultraviolet (DUV) excitation Raman spectroscopy, which is powerful tool for characterization of layers with submicron thickness. The qualities of the PCVD grown films depend strongly on a C/Si ratio (atomic ratio of C and Si in supplied source gases) and a SiH_4 flow rate. The 4H-SiC film with excellent crystallinity and surface morphology (Ra=0.21nm) can be obtained at a C/Si ratio of 0.4 for a SiH_4 flow rate of 0.020sccm.