TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Diamond Product: The first layer is essentially devoid of pinholes and the damage in the second layer includes pinholes. Both the first and second layers are single crystal diamonds. EXAMPLE - Synthetic single crystal diamond substrates measuring 3 mm x 3 mm x 2 mm with a (100) orientation were mounted on a silicon wafer. Ion implantation was performed at room temperature at a low ion dose of 1 x 10 power 16 carbon atoms/cm2 at a low energy of 175 keV to produce a layer of 50 nrn of non-diamond carbon i.e. a black damaged layer below the top surface of the substrates. There was a 50 nm thick diamond cap layer above the non-diamond carbon layer. The substrates were originally yellow and clear but developed a black, opaque surface after ion implantation.    One substrate (B) was annealed at 950 degrees C for 2 hours in 1 atmosphere of argon. Homoepitaxial growth was then performed at 830 degrees C in a microwave CVD system for 28 hours with 800 watts of input power and a pressure of 30 Torr. The input gas stream was composed of 2.3 sccm of methane, 1 sccm of oxygen and 100 sccm of hydrogen. The resulting films were about 15 microns thick.    The assemblies retained their black layers of non-diamond carbon and transmitted light microscopy revealed numerous pinholes across the grown film on substrate (A) which was not annealed but none on annealed substrate (B), on the 3 mm x 3 mm surface.    After diamond growth, assemblies (A) and (B) were exposed to a non-contact electrochemical etch to dissolve the non-diarnond carbon layer and thus separate the diamond product from the rest of the substrate. Each assembly was placed between a pair of platinum gauze electrodes spaced 2 cm apart. The electrodes and assemblies were immersed in distilled water containing sufficient chromic acid to allow 100 ma of current flow with 200 volts of applied bias. The electrodes were immersed in distilled water to a depth of 1 cm. This allowed control of the etch rate and observation of etch progress as the black damaged layer disappeared. Subsurface gas evolution was monitored visually and controlled with the applied bias, thus reducing any risk of breaking the grown diamond film due to trapped gas generated during delamination.    Separation time was about 10 hours for assembly (B). It took about 6 hours to remove all the dark material, but the diamond film grown on substrate (A) could not be removed intact due to its pinholes.