Morphology of the Diamond Thin Films Grown by Microwave Plasma Chemical Vapor Deposition with Different Aftertreatments

Abstract

Diamond films were deposited on (111) silicon wafers by microwave plasma chemical vapor deposition (MPCVD). The deposition parameters included a system power of 1200 W, chamber pressure of 110 torr, H2 flowing rate of 300 sccm, and a CH4 flowing rate of 15 sccm. The diamond particles measured about 5-6 μm, and morphology analysis revealed a rectangular structure stacked regularly on diamond films after deposition. X-ray diffraction (XRD) analysis detected (220) square structures. Annealing at 600 °C improved the quality of diamond film, making the peak of the Raman spectra at 1350 cm-1 sharper and higher. The (220) and (311) orientation structures on the diamond films decreased after annealing broke the surface morphology. To conduct electric and optical experiments conveniently, the deposited samples were immersed in acid (HNA, HF：HNO3：CH3COOH = 3：25：10) to remove the silicon layers. The HNA acid did not corrode diamond films seriously, but slightly damaged the incomplete (220) and (311) structures.