Semiconductor light emitting device and manufacturing method therefor

• US 6,996,150 B1
• Filed: 06/27/2000
• Issued: 02/07/2006
• Est. Priority Date: 09/14/1994
• Status: Expired due to Fees

• Current Assignee: ROHM Co., Ltd.
• Original Assignee: ROHM Co., Ltd.
• Inventors: Shakuda, Yukio
• Primary Examiner(s): Harvey, Minsun O.
• Assistant Examiner(s): NGUYEN, TUAN N
• Application Number:
  US09/604,097
• Time in Patent Office: 2,051 Days
• Field of Search: 372/45, 372/46
• US Class Current: 372/46.01
• CPC Class Codes: H01L 33/007 comprising nitride compounds
• CPC Class Codes: H01L 33/12 with a stress relaxation structure, e.g. buffer layer
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01S 2301/173 The laser chip comprising special buffer layers, e.g. dislocation prevention or reduction
• CPC Class Codes: H01S 2304/04 MOCVD or MOVPE
• 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 5/0422 with n- and p-contacts on the same side of the active layer
• CPC Class Codes: H01S 5/2004 Confining in the direction perpendicular to the layer structure
• CPC Class Codes: H01S 5/2009 by using electron barrier layers
• CPC Class Codes: H01S 5/22 having a ridge or stripe structure
• CPC Class Codes: H01S 5/2231 with inner confining structure only between the active layer and the upper electrode
• CPC Class Codes: H01S 5/32 comprising PN junctions, e.g. hetero- or double- heterostructures H01S5/34, H01S5/36 take precedence
• CPC Class Codes: H01S 5/3211 characterised by special cladding layers, e.g. details on band-discontinuities
• CPC Class Codes: H01S 5/3213 asymmetric clading layers
• CPC Class Codes: H01S 5/32341 blue laser based on GaN or GaP

Abstract

A semiconductor light emitting device of double hetero junction includes an active layer and clad layers. The clad layers include an n-type layer and p-type layer. The clad layers sandwich the active layer. A band gap energy of the clad layers is larger than that of the active layer. The band gap energy of the n-type clad layer is smaller than of the p-type clad layer.

Claims

1. A semiconductor light emitting device comprising:

an electrode;

a substrate;

gallium nitride type compound semiconductor layers forming a light emitting portion, said semiconductor layers including at least an n-type layer and a p-type layer, a band gap energy of the p-type layer being greater than a band gap energy of the n-type layer, said semiconductor layers being between said electrode and said substrate; and

a buffer region interposed between said substrate and said semiconductor layers, said buffer region alleviating strain resulting from a lattice mismatch between said substrate and said semiconductor layers, wherein said buffer region comprises a first layer, said first layer including In.

2. The semiconductor light emitting device according to claim 1, wherein said buffer region includes a second layer formed at a first temperature on said substrate, and wherein said first layer includes the elements In, Ga, and N, said first layer being formed at a second temperature higher than said first temperature.

3. The semiconductor light emitting device according to claim 1, wherein the conductivity of the first layer is greater than the conductivity of the second layer.

4. The semiconductor light emitting device according to claim 3, wherein the second layer consists of a semiconductor layer of high resistance.

5. The semiconductor light emitting device according to claim 1, wherein said buffer region further comprises a second layer formed at a first temperature on the surface of said substrate, wherein said first layer is formed at a second temperature higher than said first temperature, said first layer being between said second layer and said semiconductor layers, said light emitting device further including a p-type contact layer between said semiconductor layers and said electrode.

6. The semiconductor light emitting device according to claim 5, wherein said p-type contact layer consists of essentially GaN.

7. The semiconductor light emitting device according to claim 1, wherein said buffer region further comprises a second layer formed at a first temperature on the surface of said substrate, wherein said first layer includes the elements In, Ga, and N, and said first layer is formed at a second temperature higher than said first temperature, said first layer being between said second layer and said semiconductor layers, said light emitting device further including a p-type contact layer between said semiconductor layers and said electrode.