P-contact for GaN-based semiconductors utilizing a reverse-biased tunnel junction

• US 6,526,082 B1
• Filed: 06/02/2000
• Issued: 02/25/2003
• Est. Priority Date: 06/02/2000
• Status: Expired due to Term

• Current Assignee: Lumileds LLC (Apollo Global Management, Inc.)
• Original Assignee: Lumileds Lighting US LLC (Apollo Global Management, Inc.)
• Inventors: Hasnain, Ghulam, Schneider, Richard P. Jr., Corzine, Scott W.
• Primary Examiner(s): Ip, Paul
• Assistant Examiner(s): MONBLEAU, DAVIENNE N
• Application Number:
  US09/586,406
• Time in Patent Office: 998 Days
• Field of Search: 372/44, 372/45, 372/43, 372/46, 372/47, 257/103, 257/106
• US Class Current: 372/46.01
• CPC Class Codes: H01S 2301/14 Semiconductor lasers with special structural design for lasing in a specific polarisation mode
• CPC Class Codes: H01S 5/10 Construction or shape of the optical resonator , e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region H01S5/20 takes precedence
• CPC Class Codes: H01S 5/32341 blue laser based on GaN or GaP
• CPC Class Codes: H01S 5/4037 with active layers in more than one orientation

Abstract

A light-generating device such as a laser or LED. A light-generating device according to the present invention includes a first n-electrode layer in contact with a first n-contact layer, the first n-contact layer including an n-doped semiconductor. Light is generated by the recombination of holes and electrons in an n-p active layer. The n-p active layer includes a first p-doped layer in contact with a first n-doped layer, the first n-doped layer being connected electrically with the first n-contact layer. A p-n reverse-biased tunnel diode constructed from a second p-doped layer in contact with a second n-doped layer is connected electrically such that the second p-doped layer is connected electrically with the first p-layer. A second n-contact layer constructed from an n-doped semiconductor material is connected electrically to the second n-doped layer. A second n-electrode layer is placed in contact with the second n-contact layer. The various layers of the invention can be constructed from GaN semiconductors. The p-n reverse-biased tunnel diode includes an n-depletion region in the second n-doped layer and a p-depletion region in the second p-doped layer, the n-depletion region and the p-depletion region in contact with one another. The conductivity of the reverse-bias tunnel diode may be increased by doping the n-depletion region and p-depletion region. The conductivity of the reverse-bias tunnel diode can also be increased by including a compressively strained InGaN layer in the n-depletion region.

Claims

1. A light generating device comprising:

a first n-electrode layer;

an active region for generating light in response to the recombination of holes and electrons in said active region, said active region comprising a first p-doped layer comprising GaN and a first n-doped layer comprising GaN, said first n-doped layer being connected electrically with said first n-electrode;

a reverse-biased tunnel diode comprising a second n-doped layer comprising GaN and connected electrically with said first p-doped layer; and

a second n-electrode layer connected electrically with said second n-doped layer.

2. The light generating device of claim 1 further comprising an n-cladding layer in contact with said first n-doped layer and a p-cladding layer in contact with said first p-doped layer.

3. The light generating device of claim 2 wherein said n-cladding layer and said p-cladding layer comprise GaN semiconductors.

4. The light generating device of claim 1 wherein said reverse-biased tunnel diode comprises an n-depletion region in said second n-doped layer and a p-depletion region in a p-doped layer comprising GaN and adjacent to said second n-doped layer, said n-depletion region and said p-depletion region in contact with one another.

5. The light generating device of claim 4 wherein said n-depletion region is doped to a density of 10¹⁹ atoms/cm³ or greater with Si.

6. The light generating device of claim 5 wherein said p-depletion region is doped with Mg atoms to a density of 10¹⁹ atoms/cm³ or greater.

7. The light generating device of claim 1 wherein said reverse-biased tunnel diode comprises a compressively strained InGaN layer.

8. The light generating device of claim 1 further comprising a substrate, wherein said second n-doped layer is disposed between said substrate and said first p-doped layer.

9. The light generating device of claim 1 further comprising a substrate, wherein said first p-doped layer is disposed between said substrate and said second n-doped layer.