A method of preparing a monocrystalline donor substrate, the method comprising (a) implanting helium ions through the front surface of the monocrystalline donor substrate to an average depth D1 as measured from the front surface toward the central plane; (b) implanting hydrogen ions through the front surface of the monocrystalline donor substrate to an average depth D2 as measured from the front surface toward the central plane; and (c) annealing the monocrystalline donor substrate at a temperature sufficient to form a cleave plane in the monocrystalline donor substrate. The average depth D1 and the average depth D2 are within about 1000 angstroms.