| 摘要 |
A method of manufacturing doped diamond on a substrate by microwave plasma chemical vapour deposition. The substrate is located in a chamber and processing gas which includes at least one gaseous dopant selected from at least one of boron, silicon, sulphur, phosphorous, lithium and beryllium at a concentration of at least 0.01 ppm and/or nitrogen at a concentration of at least 3 ppm is injected into the chamber from a nozzle which opposes the substrate. The process gases are injected at a flow rate of at least 500 standard cm3/min and/or through one or nozzles with a Reynolds number of 1-100. Also claimed are: a diamond wafer with a longest dimension of at least 140 mm and comprising a dopant with a concentration which varies by no more that 50 % of mean concentration over at least 70 % of its volume; a layer of single crystal diamond with a thickness greater than 50 microns and at least 2x1020 boron atoms/cm3; and a single crystal diamond with adjacent doped and undoped layers, where the doping concentration varies by a factor of at least 3 over a thickness of 10 microns or less across the interface between said layers. |
