POWER SAVING ANALYSIS AND EXPERIMENTS FOR LARGE SCALE GLOBAL OPTIMIZATION

A diamond wafer including a substrate and a (111) oriented polycrystalline diamond film grown on the substrate for making surface acoustic wave devices, semiconductor devices or abrasion-resistant discs. The (111) oriented film is produced by supplying a lower carbon concentration gas and a higher carbon concentration gas alternately. The lower carbon concentration means 0% to 1% of the atomic ratio C/H. The higher carbon concentration means 1% to 8% of the atomic ratio C/H. More than 40% of layered defects are either parallel with or slanting at an angle less than 5 degrees to the surface. The wafer is monotonously distorted with a distortion height H satisfying 2 mu m