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US 4,731,790 AGranted
Semiconductor laser chip having a layer structure to reduce the probability of an ungrown region
AssigneeHitachi, Ltd.
InventorMasaaki Sawai
Life of this patent
Estimating the term…
Abstract
A semiconductor laser chip having a buried heterostructure comprising a semiconductor substrate and a light emitting portion wherein the active layer and buried layers of the light emitting portion are disposed to be on only a portion of the semiconductor substrate. By virtue of this arrangement, the probability of occurrence of V.sub.TH effects can be reduced. Also, the occurrence of the junction short-circuits resulting from an overhanging electrode or from deposition of foreign matter can be reduced.
Claims13
A semiconductor laser chip comprising:
- (1) A semiconductor substrate of a first conductivity type having first and second major surfaces;
- (2) a light emitting portion disposed on the the first major surface of said semiconductor substrate of the first conductivity type, and including:
- (a) a first semiconductor layer of the first conductivity type coming into contact with said semiconductor substrate of the first conductivity type;
- (b) an active layer serving as a light emitting region coming into contact with said first semiconductor layer of the first conductivity type;
- (c) a second semiconductor layer of a second conductivity type opposite to said first conductivity type, coming into contact with said active layer;
- (d) third semiconductor layers of the second conductivity type, formed on said first semiconductor layer of the first conductivity type, and interposing therebetween a part of said first semiconductor layer of the first conductivity type, said active layer and a part of said second semiconductor layer of the second conductivity type;
- and
- (e) fourth semiconductor layers of the first conductivity type, formed on said third semiconductor layers of the second conductivity type, and interposing therebetween said second semiconductor layer of the second conductivity type, and
- (3) a pair of electrodes for supplying a voltage to forward bias said semiconductor laser chip,
- wherein said active layer, and said second, third and fourth semiconductor layers are disposed to all be located within an area which is only over a predetermined portion of the first major surface of the substrate which is less than the entire surface area of said first major surface.
7 more elements
A semiconductor laser chip comprising:
- (1) A semiconductor substrate of a first conductivity type having first and second major surfaces;
- (2) a light emitting portion disposed on the first major surface of said semiconductor substrate of the first conductivity type, and including:
- (a) a first semiconductor layer of the first conductivity type coming into contact with said semiconductor substrate of the first conductivity type;
- (b) an active layer serving as a light emitting region into contact with said first semiconductor layer of the first conductivity type;
- (c) a second semiconductor layer of a second conductivity type opposite to said first conductivity type, coming into contact with said active layer;
- (d) third semiconductor layers of the second conductivity type, formed on said first semiconductor layer of the first conductivity type, and interposing therebetween a part of said first semiconductor layer of the first conductivity type, said active layer and a part of said second semiconductor layer of the second conductivity type;
- and
- (e) fourth semiconductor layers of the first conductivity type, formed on said third semiconductor layers of the second conductivity type, and interposing therebetween said second semiconductor layer of the second conductivity type, and
- (3) a pair of electrodes for supplying a voltage to forward bias said semiconductor laser chip,
- wherein said active layer, and said second, third and fourth semiconductor layers are disposed to all be located within an area which is only over a predetermined portion of the first major surface of the substrate which is less than the entire surface area of said first major surface,
- wherein said light emitting portion includes a top surface, sidewalls and a pn junction of said third and fourth semiconductor layers formed at the surface of said sidewalls, said semiconductor laser chip further comprising insulating films formed over said sidewalls and at least a first predetermined part of said top surface.
8 more elements
Dependencies are inferred from the claim text.