摘要 |
In a preferred embodiment, a technique and associated apparatus for producing heteroepitaxial semi-conductor junctions preferably for Group III-V compounds in an improved liquid-solid transport method, placing a prescribed doped "limited-volume" melt directly upon a host substrate and treating these in a very precisely controlled heating-cooling schedule and associated equipment whereby the substrate is melt-back to a prescribed degree, and then very carefully recrystallized in a crystal layer of the desired volume and stoichiometry (determined by the melt-volume). This is preferably effected by transport through a vertical temperature gradient; with the seed crystal (or melt) used as a saturation source to effect melt-back and such that the doping at the junction is effected by substrate dopant and melt dopant; the effect will be to enhance regrowth of a perfect epitaxial junction already formed, like a junction formed from a gallium, unsaturated aluminum-zinc melt on a gallium arsenide substrate, the substrate crystal serving as a saturation source. Preferably the Peltier cooling of the liquid-seed interface is used for fine control of the cooling and interface temperature, resulting in very low dislocation counts and high radiation efficiency and speed for junctions used as light emitters.
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