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US 5,571,747 AGranted
Method for producing a semiconductor commutator
AssigneeCanon Kabushiki Kaisha
InventorsToru Koizumi, Hidemasa Mizutani
Life of this patent
Estimating the term…
Abstract
A semiconductor commutator which is constructed by joining a semiconductor region of the first conductivity type and a semiconductor region of the second conductivity type, wherein there is provided a grain boundary which is located near a junction surface of the semiconductor region of the first conductivity type and the semiconductor region of the second conductivity type so as not to cross said junction surface.
Claims7
A method for producing a semiconductor commutator comprising the steps of:
- preparing a substrate having a free surface comprising plural nucleation surfaces and a non-nucleation surface arranged on the free surface, each of the nucleation surfaces (1) having a respective nucleation density sufficiently higher than a nucleation density of the non-nucleation surface, and (2) having a sufficiently small area, to grow only one monocrystal from a nucleus correspondingly produced on each of the nucleation surfaces;
- growing a monocrystal on each of the nucleation surfaces so as to form a grain boundary between adjacent monocrystals;
- introducing into at least one of the monocrystals a high concentration of an impurity for controlling a conductivity type to form a monocrystalline semiconductor region of a first conductivity type, to form a junction between the monocrystalline semiconductor region of the first conductivity type and another semiconductor region including the gain boundary and having a second conductivity type, wherein the gain boundary is outside a depletion region formed at the junction at a distance within a carrier diffusion length (Lp) from an edge of the depletion region and acts as a recombination center for excess minority carriers;
- and
- forming first and second electrodes respectively electrically connected to the monocrystalline semiconductor region of the first conductivity type and to the semiconductor region having the second conductivity type.
2 more elements
A method for producing a semiconductor commutator comprising the steps of:
- producing at least first and second monocrystalline semiconductor grains so as to form therebetween a grain boundary that acts as a recombination center for excess minority carriers;
- introducing into at least the first monocrystalline semiconductor grain a high concentration of an impurity to control the conductivity type to be a first conductivity type, thereby forming a monocrystalline semiconductor region of the first conductivity type having no grain boundary, a semiconductor region having the grain boundary formed between the first and second monocrystalline semiconductor grains, and a junction between the monocrystalline semiconductor region of the first conductivity type and the semiconductor region having the gain boundary, wherein the grain boundary is outside a depletion region formed at the junction at a distance within a carrier diffusion length (Lp) from an edge of the depletion region.
Dependencies are inferred from the claim text.