Diamond films grown by a 60-kW microwave plasma chemical vapor deposition system

Abstract In order to use chemical vapor deposition (CVD) diamond films for electronic devices, it is necessary to establish technologies for producing diamond wafers with controlled quality. Most of existing diamond CVD systems are, however, designed primarily for laboratory use. To cross the technological gap between the commercial production and the laboratory experiments, the current CVD technologies of diamond must be scaled up and upgraded. Development of large-scale diamond deposition processes was undertaken by using a microwave plasma CVD system, equipped with a 915-MHz, 60-kW generator for generating a large-size plasma. Polycrystalline diamond films were deposited from a hydrogen/methane gas mixture with typical gas pressures and substrate temperatures of 80–120 torr and 800–1050°C, respectively. It was found that depending on the growth conditions, the deposited films have various surface morphologies. Some of the samples have well-defined {111} and {100} facets of up to tens of micrometers in size. The Raman spectra had an intense main peak due to diamond at 1333 cm−1 without a trace of non-diamond carbon. The film quality in terms of Raman spectra was relatively uniform across the samples of 100 mm in diameter. Both 〈111〉 and 〈001〉 textured diamond films were obtained by selected growth conditions.