An experimental investigation of high pressure synthesis of diamond films using microwave plasma cavity reactor

Abstract

Summary form only given. Uniform diamond film deposition over 2 dia. Si substrates is experimentally investigated using a microwave plasma disk reactor and CH/sub 4//H/sub 2/ gas mixtures. The microwave plasma reactor is of the type developed at Michigan State University where the plasma is formed inside a 5 dia. disk-like discharge region located at one end of a cylindrical cavity applicator. The applicator employs the internal tuning, i.e., sliding short and probe variation, to match the input impedance of the plasma loaded applicator to the feed waveguide impedance. The applicator also employs a water cooling stage to control substrate temperature. The input experimental variables are (1) CH/sub 4//H/sub 2/=c which varies from 1%/spl sim/8%, (2) total flow rate which varies from 400/spl sim/1400 seem, (3) input power 3 KW/spl sim/4.5 KW, (4) pressure 80/spl sim/150 Torr, (5) substrate temperature T/sub s/ which varies from 950/spl sim/1125 C, (6) deposition time 5/spl sim/100 h. The deposited films were characterized by (1) measuring their uniformity over 2 dia., (2) growth rate in /spl mu/m/h and mg/h, (3) Raman Spectra, (4) film morphology and (5) film texture.