High-power microwave plasma reaction unit for chemical vapor deposition of diamond films

The invention provides a high-power microwave plasma reaction unit for chemical vapor deposition of diamond films. The reaction unit comprises a cylindrical resonant cavity, wherein the cylindrical resonant cavity is divided into an upper cavity, an intermediate cavity and a lower cavity; the diameter of the intermediate cavity is smallest; the top of the upper cavity is conical, and a circular ring-shaped quartz microwave window and a discoid coupling antenna are mounted in the upper cavity; the bottom of the lower cavity is provided with a main gas outlet; a first cylindrical reflector, a second cylindrical reflector and a cylindrical base, which are assembled in a sleeving way, are mounted in the lower cavity and are lifted respectively through respective lifting mechanisms. The reaction unit provided by the invention is convenient to adjust, can accommodate high microwave power, has high microwave coupling capability and high microwave focusing capability, ensures uniform distribution of reactant gas, and can prepare high-purity diamond film material at a higher rate.