钽阴极在热阴极辉光放电中行为与防护

Behavior and protection of tantalum cathode in a hot cathode glow discharge

为快速沉积高品质金刚石膜，建立了热阴极等离子体化学气相沉积方法．相对于常规冷阴极辉光放电而言，热阴极辉光放电是一种新型放电形式，具有许多新的特性，其中重要一方面是阴极工作在较高的温度（700～1200℃）．研究了钽阴极在此温度条件下，在PCVD气氛中的反应情况．结果表明，钽与气氛中的碳反应形成了有益于放电和阴极防护的碳化钽表面，而气氛中氧的存在会影响阴极的正常工作，甚至造成阴极损坏．为有效保护阴极，需严格控制真空系统的本底真空度和漏气率．

Hot cathode chemical vapor deposition method was established in order to deposit highquality diamond films with high deposition rate. Compared with the conventional cold cathode glow discharge, the hot cathode glow discharge is a new type of gas discharge. It has many new characters, one of which is that the cathode is in a hot state with the temperature about 700 - 1 200 ℃. The reaction and protection of tantalum cathode in the PCVD ambient under such temperature range were discussed. The research results showed that tantalum reacted with carbon to form a TaC layer on the surface of the cathode, which was beneficial to the discharge and the protection of the cathode. However, the existence of oxygen in the ambient is harmful to the cathode. So it is necessary to control the base pressure and leakage of the vacuum system to guarantee the normal function of the cathode.