Migration-proof light-emitting semiconductor device and method of fabrication
AssigneeSanken Electric Co., Ltd.
InventorsHidekazu Aoyagi, Takashi Kato, Tetsuji Matsuo
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Abstract
An LED has a light-generating semiconductor region formed on an electroconductive baseplate via a reflector layer of silver or silver-base alloy. The light-generating semiconductor region has an active layer between claddings of opposite conductivity types. An anti-migration sheath envelopes either or both of the reflector layer and light-generating semiconductor region in order to prevent the reflector metal from migrating onto the semiconductor region with the consequent possible short-circuiting of the claddings of the active layer.
Claims19
A light-emitting semiconductor device protected against the migration of metal, comprising:
- (a) a baseplate;
- (b) a conductor layer formed on the baseplate, the conductor layer being made from a metal that is relatively easy to migrate;
- (c) a light-generating semiconductor region coupled to the baseplate via the conductor layer and comprising at least two semiconductor layers of opposite conductivity types for generating light;
- (d) an electrode on the light-generating semiconductor region;
- and
- (e) an anti-migration sheath enveloping at least either of the conductor layer and the light-generating semiconductor region for preventing the metal of the conductor layer from migrating onto the light-generating semiconductor region, the anti-migration sheath being higher in electric resistivity than the conductor layer and the light-generating semiconductor region.
A method of fabricating a light-emitting semiconductor device protected against the migration of meal, which comprises:
- (a) successively growing at least two semiconductor layers of opposite conductivity types in a vapor phase on a substrate for creating a semiconductor region capable of generating light, the light-generating semiconductor region having a first major surface facing away from the substrate and a second major surface held against the substrate;
- (b) bonding a baseplate to the first major surface of the light-generating semiconductor region with a bonding metal that is relatively easy to migrate, the bonding metal creating a conductor layer between the light-generating semiconductor region and the baseplate;
- (c) removing the substrate from the second major surface of the light-generating semiconductor region;
- (d) forming an electrode on the light-generating semiconductor region;
- and
- (e) creating an anti-migration sheath around at least either of the conductor layer and the light-generating semiconductor region for preventing the metal of the conductor layer from migrating onto the light-generating semiconductor region, the anti-migration sheath being higher in electric resistivity than the conductor layer and the light-generating semiconductor region.
Dependencies are inferred from the claim text.