Light-emitting device

• US 8,872,174 B2
• Filed: 05/20/2013
• Issued: 10/28/2014
• Est. Priority Date: 06/01/2012
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei
• Primary Examiner(s): Nguyen, Dao H
• Assistant Examiner(s): Nguyen, Tram H
• Application Number:
  US13/897,501
• Publication Number:
  US 20130320331A1
• Time in Patent Office: 526 Days
• Field of Search: 257/40, 257 79-103, 257/918, 257E51018-E51022, 257E33001-E33077, 257/E33.054, 257/E23.028, 257/E25.032, 257/E31.058, 257/E31.063, 257/E31.115, 257E27133-E27139, 257252-254, 257257-258, 257/458, 257/656, 257/E29.336, 257/E31.036, 257E31087-E31088, 257E31061-E31062, 257/192, 257E29246-E29253, 257/E21.403, 257/E21.407, 257/194, 257/285, 257 9- 39, 257/E39.003, 257E39012-E39015, 257/E29.042, 257/E29.179, 257642-643, 257/759, 257E51001-E51052, 257E25008-E25009, 257E29069-E29071, 257/E29.245, 257E49001-E49004, 257/E21.404, 438 22- 47, 438/69, 438/493, 438/503, 438/507, 438/956, 438/183, 438/926, 438/167, 438/172, 438292-308, 438/82, 438/99, 438/16, 438/65
• US Class Current: 257/43
• CPC Class Codes: H01L 33/0066 with a substrate not being a III-V compound
• CPC Class Codes: H01L 33/16 with a particular crystal structure or orientation, e.g. polycrystalline, amorphous or porous
• CPC Class Codes: H01L 33/30 containing only elements of Group III and Group V of the Periodic Table
• CPC Class Codes: H01L 33/32 containing nitrogen

Abstract

To provide a novel light-emitting device that can be manufactured with high productivity. In a light-emitting device in which a light-emitting diode (LED) layer is provided over a substrate, a metal oxide semiconductor (c-axis aligned crystalline oxide semiconductor (CAAC-OS)) substrate including a crystal part having a c-axis which is substantially perpendicular to a surface of the substrate is used as the substrate. The substrate may have either a single-layer structure of a CAAC-OS substrate or a structure in which a thin CAAC-OS substrate is stacked over a base substrate.

Claims

1. A light-emitting device comprising:

a light-emitting layer over a substrate,

wherein the substrate comprises a c-axis aligned crystalline oxide semiconductor, and

wherein the c-axis aligned crystalline oxide semiconductor comprises indium, gallium and zinc.

2. The light-emitting device according to claim 1, wherein a surface of the substrate is formed of the c-axis aligned crystalline oxide semiconductor.

3. The light-emitting device according to claim 1, wherein the substrate is formed over a base substrate.

4. The light-emitting device according to claim 1, further comprising:

a buffer layer between the substrate and the light-emitting layer.

5. The light-emitting device according to claim 1 is a light-emitting diode.

6. A method for manufacturing a light-emitting device, comprising the steps of:

forming a substrate comprising a c-axis aligned crystalline oxide semiconductor; and

forming a light-emitting layer over the substrate,

wherein the c-axis aligned crystalline oxide semiconductor comprises indium, gallium, and zinc.

7. The method according to claim 6, wherein a surface of the substrate is formed of the c-axis aligned crystalline oxide semiconductor.

8. The method according to claim 6, wherein the substrate is formed over a base substrate.

9. The method according to claim 6, wherein the step of the formation of the light-emitting layer comprises the steps of:

forming a first clad layer over the substrate;

forming a first light-emitting layer over the first clad layer; and

forming a second clad layer over the first light-emitting layer.

10. The method according to claim 6, further comprising the step of:

forming a buffer layer over the substrate before the step of the formation of the light-emitting layer.

11. The method according to claim 6, wherein the step of the formation of the substrate comprises the steps of:

grinding a material comprising an oxide semiconductor;

molding the material after grinding;

baking the material; and

performing a pressure treatment on the material.

12. The method according to claim 11, wherein the steps of molding the material, baking the material and performing the pressure treatment are performed more than once.

13. A light-emitting device comprising:

a light-emitting layer over a substrate,

wherein the substrate comprises a c-axis aligned crystalline oxide semiconductor, and

wherein the c-axis aligned crystalline oxide semiconductor comprises indium, gallium and zinc,

wherein the light-emitting layer comprises a first clad layer, a first light-emitting layer over the first clad layer, and a second clad layer over the first light-emitting layer, and

wherein each of the first clad layer, the first light-emitting layer, and the second clad layer comprises a Group 13-15 compound semiconductor.

14. The light-emitting device according to claim 13, wherein a surface of the substrate is formed of the c-axis aligned crystalline oxide semiconductor.

15. The light-emitting device according to claim 13, wherein the substrate is formed over a base substrate.

16. The light-emitting device according to claim 13,

wherein the first clad layer is an n-type semiconductor and the second clad layer is a p-type semiconductor.

17. The light-emitting device according to claim 13, further comprising:

a buffer layer between the substrate and the light-emitting layer.

18. The light-emitting device according to claim 13 is a light-emitting diode.