Light emitting semiconductor device having reflection layer structure

• US 6,492,661 B1
• Filed: 11/04/1999
• Issued: 12/10/2002
• Est. Priority Date: 11/04/1999
• Status: Expired due to Term

• Current Assignee: Unit Light Technology Incorporated
• Original Assignee: Unit Light Technology Incorporated
• Inventors: Hon, Schang-Jing, Chien, Fen-Ren, Lai, Mu-Jen
• Primary Examiner(s): Tran, Minh Loan
• Application Number:
  US09/434,316
• Time in Patent Office: 1,132 Days
• Field of Search: 257/98, 257/103, 257/94, 372/45, 372/46, 372/50, 372/99
• US Class Current: 257/98
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/145 with a current-blocking structure
• CPC Class Codes: H01L 33/405 Reflective materials

Abstract

A light-emitting device with a reflection layer is disclosed. The reflection layer is formed on a light emitting stack structure. A second substrate is subsequently combined with the reflection layer, and then the original substrate of the stack structure is removed, such that the second substrate becomes the substrate of the device. The reflection layer can effectively reflect the light emitted from the light emitting stack structure and directed to the substrate, and thus can increase the light-emitting efficiency of a surface-emitting type light-emitting device. The invention can also convert a light-emnitting device using an insulated substrate to be the one having vertical type electrode structure so as to effectively reduce the wafer area used for a die and facilitate subsequent wiring and packaging processes using traditional mechanisms.

Claims

1. A light-emitting device comprising

a semiconductor stack structure for generating light in response to a conduction of current;

a reflection layer provided on a main surface of said semiconductor stack structure for reflecting light generated from said stack structure and directed to said reflection layer, said reflection layer including at least one region with inferior conductivity functioning as a current-block region;

a thick layer positioned on said reflection layer and functioning as a substrate; and

electrode structure for applying a current to said semiconductor stack structure.

2. The device as set forth in claim 1, wherein said current-block region includes a Schottky contact region including at least one of the following:

insulated oxide, insulated nitride, and air.

3. The device as set forth in claim 1, wherein said reflection layer is a single layer structure including at least one of titanium (Ti), aluminum (Al) and gold (Au), or a multiple layer structure of gold/germanium (Au/Ge), titanium/aluminum (ti/Al) and nickel/gold (Ni/Au).

4. The device as set forth in claim 1, wherein said semiconductor stack structure comprises:

a lower cladding layer having a first conductive type;

an upper cladding layer having a second conductive type and being adjacent to said lower cladding layer; and

an ohmic contact layer formed on said upper cladding layer.

5. The device as set forth in claim 4, wherein said semiconductor stack structure further comprises an active layer between said lower cladding layer and said upper cladding layer.

6. The device as set forth in claim 4, wherein said lower cladding layer is an n type AlGaInP semiconductor layer and said upper cladding layer is a p type AlGaInP semiconductor layer.

7. The device as set forth in claim 4, wherein said lower cladding layer is an n type gallium nitride-based III-V compound semiconductor layer and said upper cladding layer is a p type gallium nitride-based III-V compound semiconductor layer.

8. The device as set forth in claim 1, wherein the material of said thick layer includes at least one of the following:

indium-tin oxide (ITO), zinc oxide (Zn)), a compound semiconductor consisting of germanium (Ge) and silicon (Si), and a compound semiconductor consisting of gallium phosphide (GaP) and indium phosphide (InP).

9. The device as set forth in claim 1, wherein said electrode structure comprises two electrodes positioned on the surface of said thick layer and the surface of the said stack structure opposite to said main surface, respectively.