Semiconductor light emission device

• US 6,072,818 A
• Filed: 03/28/1997
• Issued: 06/06/2000
• Est. Priority Date: 03/28/1996
• Status: Expired due to Term

• Current Assignee: Nichia Corporation
• Original Assignee: Fuji Photo Film Co Limited (Fujifilm Holdings Corporation)
• Inventors: Hayakawa, Toshio
• Primary Examiner(s): Bovernick, Rodney
• Assistant Examiner(s): Leung, Quyen Phan
• Application Number:
  US08/827,252
• Time in Patent Office: 1,166 Days
• Field of Search: 372/45, 372/46, 257/745, 257/743
• US Class Current: 372/46.014
• CPC Class Codes: H01S 2301/176 Specific passivation layers on surfaces other than the emission facet
• CPC Class Codes: H01S 5/0213 Sapphire, quartz or diamond based substrates
• CPC Class Codes: H01S 5/0421 characterised by the semiconducting contacting layers electrodes H01S5/0425
• CPC Class Codes: H01S 5/04257 having positive and negative electrodes on the same side of the substrate
• CPC Class Codes: H01S 5/22 having a ridge or stripe structure
• CPC Class Codes: H01S 5/32341 blue laser based on GaN or GaP

Abstract

A semiconductor light emission device includes at least an n-type semiconductor clad layer, a semiconductor active layer and a p-type semiconductor clad layer formed on a substrate in this order. A stripe portion which determines a light emission region is formed on a part of the p-type clad layer and a p-type capping layer is formed on the stripe portion. A p-side electrode is formed on the p-type capping layer. The p-type capping layer includes a lower capping layer in the form of a stripe overlaid on the stripe portion and an upper capping layer which is formed on the lower capping layer and has an area larger than that of the lower capping layer. The contact area between the p-side electrode and the upper capping layer of the p-type capping layer is larger than that between the upper capping layer and the lower capping layer of the p-type capping layer.

Claims

1. A semiconductor light emission device comprising at least an n-type semiconductor clad layer, a semiconductor active layer and a p-type semiconductor clad layer formed on substrate in this order, a stripe portion which determines a light emission region being formed on a part of the p-type clad layer, a p-type capping layer being formed on the stripe portion and a p-side electrode being formed on the p-type capping layer wherein the improvement comprises:

said p-type capping layer comprises a lower capping layer in the form of a stripe overlaid on the stripe portion and an upper capping layer which is formed on the lower capping layer and has an area larger than that of the lower capping layer and the contact area between the p-side electrode and the upper capping layer of the p-type capping layer is larger than that between the upper capping layer and the lower capping layer of the p-type capping layer wherein the p-side electrode is formed almost entirely on the p-type capping layer;

wherein said upper capping layer comprises a portion which is overlaid on the lower capping layer and an overhang portion which stands out from the lower capping layer; and

wherein said overhang portion is formed on an insulating film formed on a part of the p-type clad other than the stripe portion.

3. A semiconductor light emission device as defined in either one of claims 1 and 2 in which said n-type clad layer, active layer, p-type clad layer and p-type capping layer are of an Al_x In_y Ga_1-n-y N(0≦

x, y≦

1) type.

2. A semiconductor light emission device comprising at least an n-type semiconductor clad layer, a semiconductor active layer and a p-type semiconductor clad layer formed on substrate in this order, a stripe portion which determines a light emission region being formed on a part of the p-type clad layer, a p-type capping layer being formed on the stripe portion and a p-side electrode being formed on the p-type capping layer wherein the improvement comprises:

said p-type capping layer comprises a lower capping layer in the form of a stripe overlaid on the stripe portion and an upper capping layer having a portion which is overlaid on the lower capping layer and an overhang portion which stands out from the lower capping layer and having an area larger than that of the lower capping layer;

wherein the overhang portion forms an air gap between the upper capping layer and the p-type clad layer; and

wherein the contact area between the p-side electrode and the upper capping layer of the p-type capping layer is larger than the contact area between the upper capping layer and the lower capping layer of the p-type capping layer wherein the p-side electrode is formed on a majority of the p-type capping layer.

4. An Al_x In_y Ga_1-n-y N(0≦

x, y≦

1) type semiconductor light emission device comprising a semiconductor layer formed on a substrate, said substrate being made of an insulating material, the semiconductor layer including at least a p-type clad layer, an active layer and an n-type clad layer formed on the substrate in this order, the semiconductor layer being electronically connected to an n-side electrode formed on the semiconductor layer only through a narrow stripe portion formed on the semiconductor layer and/or the n-side electrode, thereby causing the semiconductor light emission device to oscillate in a single mode, and a p-side electrode being formed on the side of the p-type clad layer;

wherein the contact area between the p-side electrode and the semiconductor layer is larger than the area of the stripe portion.