Adhesive-free process for bonding a semiconductor crystal to an electrically insulating, thermally conductive stratum

Claim 1

An adhesive-free process for forming a light resonant cavity and transparent heat sink suitable for use in an electron beam laser consisting of the following steps: providing a crystal of a direct band-gap semiconductor having two major broad and plano-parallel faces and a thickness therebetween not greater than approximately 60 micrometers, forming on a block of a thermally-conductive electrical insulator material selected of either quartz or sapphire a corresponding major broad and substantially planar surface, positioning a major broad surface of the crystal in contact with the major broad surface of the insulator material, bombarding the breadth of the opposite major broad surface of the crystal with a swept and pulsed electron beam for a total duration of approximately 15 minutes, said beam having an energy of approximately 40 keV, a beam current of approximately 4 ma and a beam diameter of approximately 50 μm, being swept at a rate of approximately 100 meters/sec over a raster containing approximately 125 lines and being pulsed at a rate of approximately one pulse every five microseconds, with each pulse lasting approximately 50 nanoseconds to allow heat produced at a given location in the crystal as the result of a given pulse to be dissipated into the crystal and insulating material during the period between pulses and during the period while the beam is scanned over the remainder of the crystal to avoid appreciable increases in the bulk temperature of the crystal and to ensure that the uniformity of laser characteristics of the crystal are not impaired, a uniform bond thereby being produced over substantially the entire area of the contacted surfaces of the crystal and insulator material without the application of external heat or pressure such that when the bonded crystal and insulator material are utilized in a said electron beam laser, heat generated as a result of electron bombardment during the laser emission is dissipated into the heat sink, enabling the lasing crystal to be in thermal equilibrium such that lasing threshold and wavelength of laser emission is the same over all portions of the crystal.