| 摘要 |
A method of changing the geometry of p-n or isotype junctions in semiconductor crystal material by laser or electron beam melting through a portion of the junction is described. Two adjoining regions are doped at different levels and a laser or electron beam melts through a portion of one region into the other region any desired depth. Upon cooling, the melt epitaxially recyrstallizes, producing a deformation in the otherwise planar junction that extends the more heavily doped region into the more lightly doped region. In the case of reverse-biased diodes, such as zener or avalanche diodes, this can be used to either increase the field in a portion of the depletion region, or push a portion of the junction into a more heavily doped region, or both, which reduces the breakdown voltage. Also, a method of controlling a pulsed laser or electron beam while continuously monitoring the breakdown voltage of the diode to obtain the desired breakdown voltage is described. The method is also useful for reducing the channel width of field effect transistors, and for making contact to buried doped regions and creating isolated surface regions.
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