摘要
The design and performance of an improved microwave plasma assisted chemical vapor deposition (MPACVD) reactor is described. This reactor operates with high power densities and at pressures up to 300 torr. Differences from earlier MPACVD reactor designs [4] include an increase in applicator and dome size and the excitation of the applicator with a new 鈥渉ybrid 鈥淭M0/TEM001鈥?mode. The reactor is experimentally evaluated by synthesizing single crystal diamond (SCD) at pressures from 180 to 300 torr with absorbed power densities between 400 and 1000 W/cm3. Without N2 addition SCD growth rates as high as 75 渭m/h were observed. A SCD growth window between 950 掳C and 1300 掳C was identified and within this growth window growth rates were 1.2 to 2.5 times greater than the corresponding growth rates for earlier reactor designs. SCD characterization by micro-Raman spectroscopy, SIMS, and by IR-UV transmission spectroscopy indicated that the synthesized SCD quality is that of type IIa diamond.