Quality of wide band nanocrystalline carbon layers deposited in PA CVD

Abstract

Diamond-like carbon layers were deposited onto silicon wafers by PA RF CVD method in a plasma reactor with methane as a source of carbon, and 13.56 MHz frequency generator. The technology is very sensitive to the shape of the electrodes and specimens placement on them. The experiments were conducted in the reactor with the flat upper electrode, placed parallel and very close to the RF electrode. This geometry solution was to assure the uniformity of the electric field in the active area. The tests were to show how the process parameters influence the quality of deposited films. They proved that the most significant parameter is the self-bias voltage. A change of the self-bias value caused a considerable change in the structure of the deposited carbon layer. The carbon structures were examined by TEM and AFM. Independently to the carbon forms, which prevailed in the tested films, the morphology of the obtained films was uniform on the whole RF electrode.