高等离子体功率密度下MPCVD法制备多晶金刚石膜

Preparation of polycrystalline diamond films by MPCVD at high plasma power density

通过自制的MPCVD双基片台设备,在微波功率为1400 W保持不变及中高气压,等离子体功率密度为357.5~807.4 W/cm^(3),基片温度为850±30℃,CH_(4)体积分数为1.0%~1.5%,沉积速率为1~8μm/h条件下,在直径11.5 mm的硅基片上沉积不同质量的多晶金刚石膜,并通过光谱仪、光学显微镜、拉曼光谱仪对等离子体中的氢原子及含碳基团、多晶薄膜的形貌及质量进行表征。结果表明:随着等离子体功率密度上升,等离子体椭球中的氢原子基团和含C的活性基团强度增加,金刚石膜生长速率大幅度提高,金刚石膜纯度也大幅度提升。在气压为21 kPa,等离子体功率密度为807.4 W/cm^(3),基片温度为850±30℃,生长时间为150 h,CH_(4)体积分数为1.0%及氢气流量为200 mL/min的条件下,金刚石膜的生长速率达到5μm/h,金刚石膜厚达752.0μm,金刚石拉曼峰的半高宽为6.48 cm^(−1),且生长的金刚石膜质量良好。

Through the self-made MPCVD dual-substrate platform equipment,the microwave power was 1400 W and the pressure was medium to high,the plasma power density was 357.5~807.4 W/cm^(3),the substrate temperature was 850±30℃,the volume fraction of CH_(4) was 1.0%~1.5%and the deposition rate was 1~8μm/h,the polycrystalline diamond film of different quality was deposited on the silicon substrate with a diameter of 11.5 mm.The hydrogen atoms and the C-containing groups in the plasma,the morphology and the quality of polycrystalline films were charac-terized by spectrometer,optical microscope and Raman spectrometer.The results show that with the increases of plasma power density,the strength of hydrogen atom group and active C-containing group in plasma ellipsoid increase,the growth rate and the purity of diamond film are greatly improved.When the air pressure is 21 kPa,the plasma power density is 807.4 W/cm^(3),the substrate temperature is 850±30℃,the growth time is 150 h,the CH_(4) volume fraction is 1.0%and the hydrogen flow rate is 200 mL/min,the growth rate of the diamond film reaches 5μm/h,the thickness of the diamond film reaches 752.0μm,the FWHM of the diamond Raman peak is 6.48 cm^(−1),and the quality of the grown diamond film is good.