Semiconductor light emitting light concentration device

• US 5,181,220 A
• Filed: 04/26/1991
• Issued: 01/19/1993
• Est. Priority Date: 07/16/1985
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Yagi, Tetsuya
• Primary Examiner(s): Epps, Georgia Y.
• Application Number:
  US07/691,864
• Time in Patent Office: 634 Days
• Field of Search: 372/45, 372/46, 372/96, 372/44, 357/17, 357/19, 357/30
• US Class Current: 372/45.01
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector

Abstract

A semiconductor light emitting light concentration device is described which has a multiple diffraction ring for collecting and concentrating the light emitted from an LED integrally formed into the electrode at the semiconductor substrate end of the light emitting device.

Claims

1. A method of forming a combined light emitting and light concentrating device comprising:

depositing a plurality of epitaxial layers including a light emitting region on a semiconductor substrate wherein the outside surface of said substrate constitutes the rear surface of said device and the outer surface of said plurality of layers opposed to said rear surface constitutes the upper surface of said epitaxial layers;

depositing an electrode material onto said rear surface;

depositing an electrode material onto said upper surface; and

forming integrally with at least one of said electrode surfaces, a light collecting multiple diffraction ring for collecting the light emitted from said light emitting region.

2. The method of claim 1 wherein said plurality of epitaxial layers including said light emitting regio comprises:

a buffer layer on said substrate;

a lower clad layer on said buffer layer;

an active layer on said lower clad layer;

an upper clad layer on said active layer; and

a contact layer on said upper clad layer.

3. The method of claim 2 wherein said substrate and said buffer layer comprise p-InP compounds, said lower clad layer and active layer comprise:

p-InGaAsP compounds, and

said upper clad layer and contact layer comprise n-IcGaAsP compounds.

4. The method of claim 1 wherein said light collecting multiple diffraction ring comprises:

a non-light transparent epitaxial layer laminated on said rear surface of said semiconductor substrate in a space provided at the center of the electrode on said rear surface.

5. The method of claim 4 wherein said non-light transparent epitaxial layer comprises InGaAsP.

6. The method of claim 1 wherein said multiple diffraction ring is formed by conducting an ion injection of impurities into the rear surface of said semiconductor substrate in a space provided in said electrode on said rear surface to create centers of high density in a pattern of multiple concentric rings.

7. The method of claim 1 wherein said electrode of said rear surface contains a multiple diffraction ring configuration formed of the material of said electrode.

8. The method of claim 7 wherein said electrode is formed of a metal.

9. A semiconductor light emitting and light concentrating device, comprising:

a semiconductor light emitting region having a front surface and a rear surface opposite from said front surface;

a semiconductor substrate formed at said rear surface of said semiconductor light emitting region wherein the outside surface of the substrate comprises the rear surface of the device;

a plurality of epitaxial layers including said light emitting region laminated on said semiconductor substrate, wherein said plurality of epitaxial layers including said light emitting region comprises a buffer layer formed on said semiconductor substrate, a first clad layer formed on said buffer layer, an active layer formed on said first clad layer, a second clad layer formed on said active layer, a contact layer formed on said second clad layer and an insulating layer formed on said contact layer and the outer surface of said plurality of epitaxial layers opposed to the rear surface of the device comprises the upper surface of said plurality of epitaxial layers;

a first electrode affixed to said insulating layer;

a second electrode fixed to the rear surface of said semiconductor substrate; and

a light collecting multiple diffraction ring for collecting light emitted from said light emitting region formed by conducting an ion injection of impurities into said rear surface of said substrate wherein said light collecting multiple diffraction ring has a narrower energy band gap than that of said active layer.

10. The semiconductor light emitting and light concentrating device of claim 9, wherein said plurality of epitaxial layers are formed from at least one member of the group consisting of InP, InGaAsP, InGaAs, GaAs, and GaA1As.

11. The semiconductor light emitting and light concentrating device of claim 9, wherein said semiconductor substrate and said buffer layer comprise InP, said first clad layer, said active layer, and said second clad layer comprise InGaAsP;

said contact layer comprises InGaAs; and

said insulating layer comprises silicon dioxide.