An experimental investigation of high pressure synthesis of diamond films using microwave plasma cavity reactor
- Michigan State Univ., East Lansing, MI (United States)
Uniform diamond film deposition over 2 in. 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 in. 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 deposited films were characterized by (1) measuring their uniformity over 2 in. dia., (2) growth rate in {micro}m/h and mg/h, (3) Raman Spectra, (4) film morphology and (5) film texture. Film growth rate, morphology, texture and Raman Spectra are recorded vs. CH{sub 4}/H{sub 2}, flow rate, substrate temperature and deposition time. Five hour experiments indicate that the average film growth rate varied from a few {micro}m/h with c = 1% to over 4.3 {micro}m/h at c = 3% and then decreased for high c ratios. Average growth rate also varies with flow rate with a maximum of over 5 {micro}m/h. The growth rate increases as deposition time increases and reaches a maximum growth rate of 6.3 {micro}m/h({approximately}44 mg/h) at t = 100 h. The film growth rate reaches a maximum around T{sub s} = 1,100 C for both 2% and 3% chemistries. 2 in. dia. free standing films were grown with thicknesses of 200--600 {micro}m and with uniformities of 10% over 2 in. dia. area.
- OSTI ID:
- 419785
- Report Number(s):
- CONF-960634--
- Country of Publication:
- United States
- Language:
- English
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