Diamond substrate for surface acoustic wave device, and surface acoustic wave device

摘要

A diamond film is deposited in the thickness of 20 mum on a silicon wafer 0.8 mm thick by filament CVD. Here the hydrogen content of the diamond film is adjusted in the range of not less than 1% nor more than 5% in atomic percent. By mechanical polishing with a grinding wheel including diamond abrasives, the diamond film is smoothed so that the arithmetic mean roughness (Ra) of the surface thereof becomes not more than 20 nm.