非对称磁镜场电子回旋共振氧等离子体刻蚀化学气相沉积金刚石膜

Non-symmetric magnetic mirror field ECR oxygen plasma etching CVD diamond films

分别应用郎缪尔双探针和离子灵敏探针对非对称磁镜场电子回旋共振氧等离子体的电子参数、空间分布和离子参数进行了测量,分析了气压对等离子体参数及空间分布的影响。利用该等离子体在优化的气压条件下对化学气相沉积金刚石膜进行了刻蚀,并研究了刻蚀机理。结果表明：电子温度为5～10 eV,离子温度为1 eV左右,而等离子体数密度在1010cm-3数量级。随气压的升高,电子和离子温度降低,而电子数密度先增大后减小。在低气压下等离子体数密度空间分布更均匀,优化的刻蚀气压为0.1 Pa。刻蚀过程中,离子的回旋运动特性得到了加强,有利于平行于金刚石膜表面的刻蚀,有效地保护了金刚石膜的晶界和缺陷。

The ion parameters,electronic parameters and its spatial distribution were measured respectively by ion-sensitive probe and double Langmuir probe on a non-symmetric magnetic mirror field ECR plasma apparatus.The effects of gas pressure on plasma parameters and the spatial distribution were analyzed.The etching of CVD diamond thick films was accomplished by the ECR plasma under optimized pressure conditions and the etching mechanism is studied.The results showed that the electronic temperature was 5～10 eV,the ion temperature was about 1 eV and the electron density was in the order of 1010 cm-3.With the increasing of gas pressure,the electron density increased firstly and then decreased,the temperature of the electron and ion gradually decreased.The spatial distribution of plasma density was more uniform under low pressure.The best pressure for diamond etching was 0.1 Pa.The characteristics of ion cyclotron motion were strengthened by the magnetic mirror field and was useful for the etching parallel to the surface of the diamond films,as a result,the grain boundaries and defects of diamond films were effectively protected.