Texture-controlled diamond films synthesized by microwave plasma-enhanced chemical vapour deposition

Abstract

Texture-controlled diamond films are deposited on silicon wafers in a CH4-H-2 gas mixture using microwave plasma-enhanced chemical vapour deposition and the quality of the textured films has been investigated using Raman spectroscopy. It is found that the quality of the (100) textured film is better than those of (110) or (111) textured films. The transition of the textures and the growth rates of the diamond film are observed with changing deposition parameters such as the substrate temperature (700-950 degrees C), total reaction pressure (1 333-8 000 Pa), methane concentration (0.5-5%) and microwave power (500-1 300 W). As the texture of diamond films is changed from [100] to [111] or others, the full width at half maximum and I-G/I-D ratio obtained from Raman scattering are increased. It is found that the growth rate of (100) textured film is more sensitive to the parameters of substrate temperature, pressure and methane concentration than microwave power. The growth rate of the (100) textured film is increased with increasing substrate temperature, pressure or methane concentration, and the quality of the (100) textured film is increased with decreasing growth rate. The optimum growth rate maintaining the (100) texture is about 0.6 mu m h(-1), and its deposition conditions are as follows: substrate temperature, 800 degrees C; pressure, 4 000 Pa (30 Torr); methane concentration, 2%; microwave power, 1 000 W.