The effect of frequency and duty cycle of a pulsed microwave plasma on thechemical vapor deposition of diamond

We examine the effect of a pulsed microwave discharge on the deposition rat e of polycrystalline diamond by varying the pulse repetition rate and duty cycle. A simple model of the dynamic plasma chemistry is developed in order to explain the increase in growth rate with frequency for the same average power. Changing the duty cycle while keeping the total plasma on-time cons tant resulted in the same film thickness for all duty cycles. One possible implication of this is that growth takes place when the pulse is on. (C) 19 99 American Institute of Physics. [S0021-8979(99)00920-2].