摘要
目的在实验室自制的10 kW微波等离子体化学气相沉积装置中,系统分析甲烷与氢气的流量比在高功率微波等离子体环境中对金刚石膜生长的影响。方法利用等离子体发射光谱诊断分析高功率微波等离子体放电环境的特征,同时利用SEM及Raman光谱对不同沉积条件下获得的金刚石膜的形貌及质量进行表征,以确定高功率微波馈入情况下甲烷流量的调控原则。结果微波功率的提高可以有效地增加等离子体中的电子密度,产生更多活性H原子以及CH和C2等有利于金刚石膜生长的含碳气团。在保持微波功率为5000 W、氢气流量为300 mL/min、腔体气压为13 kPa和基片温度为(950±20)℃的实验条件下,当Q(CH_4)/Q(H_2)<1.0%时,金刚石膜中二次形核现象明显,晶粒尺寸较小;当1.0%≤Q(CH_4)/Q(H_2)≤2.0%时,可获得晶粒完整且质量较高的金刚石膜;当Q(CH_4)/Q(H_2)>2.0%,金刚石膜可获得较大的晶粒,但易产生孪晶。结论提高微波功率利于活性氢原子的产生,可更充分地活化含碳大分子气体。在本实验条件下,当1.0%≤Q(CH_4)/Q(H_2)≤2.0%时,所制备的金刚石膜具有较高的质量。
The work aims to systematically analyze the influence of the gas flow ratio between CH4 and H2 on the growth of diamond films in a home-made 10 kW MPCVD system.The characteristics of plasma discharging at relative high microwave power were analyzed and studied by plasma emission spectroscopy.The morphology and quality of the deposited diamond films were characterized by scanning electron microscope and Raman spectroscopy respectively in order to determine the regulation principles of the gas flow rate of CH4 in CH4/H2 gas mixture.The increasing microwave power could effectively improve the electron density in the plasma and generate more activated H atoms as well as the species of CH and C2 beneficial to the growth of diamond films.When the microwave power,chamber pressure,substrate temperature and gas flow of H2 were kept at 5000 W,13 kPa,(950±20)℃and 300 mL/min respectively,the diamond films deposited with Q(CH4)/Q(H2)<1.0%exhibited obvious secondary nucleation phenomenon and smaller crystal size.The diamond films grown with 1.0%≤Q(CH4)/Q(H2)≤2.0%possessed well-facets crystals,and the diamond films prepared with Q(CH4)/Q(H2)>2.0%had relative lager crystals containing twins.The increasing microwave power results in an increase in the concentration of activated H atoms as well as the activation level of carbon contained gas.The diamond film prepared at 1.0%≤Q(CH4)/Q(H2)≤2.0%in current experimental conditions has the best quality.
作者
翁俊
周程
刘繁
汪建华
WENG Jun;ZHOU Cheng;LIU Fan;WANG Jian-hua(Key Laboratory of Plasma Chemistry and Advanced Materials of Hubei Province,Wuhan Institute of Technology,Wuhan 430205,China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2018年第11期202-209,共8页
Surface Technology
基金
国家自然科学基金项目(51402220)
湖北省教育厅基金项目(Q20151517)
武汉工程大学科学研究基金项目(K201506)~~
关键词
甲烷
氢气
高微波功率
微波等离子体
化学气相沉积
methane
hydrogen
high microwave power
microwave plasma
chemical vapor deposition
