Patent ID: 6051063
Filing Date: 2000-04-18
Classification: C23C,C30B,H03H

Abstract:
A diamond wafer comprising:a distorted substrate which is substantially flat in a free-standing state, anda (100) oriented polycrystalline diamond film synthesized directly on the substrate by a CVD method and polished to a roughness of less than Rmax50 nm and Ra20 nm,wherein the wafer is a circular wafer with a center and a periphery and is distorted monotonously from the center to the periphery without a deflection point,wherein the wafer has a distortion height H, which is defined as a height from the center of the wafer to a plane including a circumference of the wafer, satisfying an inequality 2 .mu.m.ltoreq..vertline.H.vertline..ltoreq.150 .mu.m, andwherein the substrate is a Si single crystal wafer, a GaAs single crystal wafer, an AlN crystal wafer, a LiNbO.sub.3 wafer, a LiTaO.sub.3 wafer, or a quartz wafer.