NITRIDE SEMICONDUCTOR DEVICE

• US 20100244046A1
• Filed: 06/10/2010
• Published: 09/30/2010
• Est. Priority Date: 05/10/2004
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Kamikawa, Takeshi, Araki, Masahiro, Yamada, Eiji
• Granted Patent: US 8,288,794 B2
• Time in Patent Office: Days
• US Class Current: 257/76
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/24 of the light emitting region, e.g. non-planar junction
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01S 2304/12 Pendeo epitaxial lateral overgrowth [ELOG], e.g. for growing GaN based blue laser diodes
• CPC Class Codes: H01S 5/0202 Cleaving
• CPC Class Codes: H01S 5/0207 Substrates having a special shape
• CPC Class Codes: H01S 5/2201 in a specific crystallographic orientation
• CPC Class Codes: H01S 5/2231 with inner confining structure only between the active layer and the upper electrode
• CPC Class Codes: H01S 5/32341 blue laser based on GaN or GaP

Abstract

On a processed substrate having an engraved region as a depressed portion formed thereon, a nitride semiconductor thin film is laid. The sectional area occupied by the nitride semiconductor thin film filling the depressed portion is 0.8 times the sectional area of the depressed portion or less.

Claims

1. A nitride semiconductor light-emitting device comprising:

a processed substrate having a depressed portion, which is an engraved region, and a ridge portion, which is a non-engraved region, formed on a substrate formed of a nitride semiconductor or comprising a nitride semiconductor as part of a surface thereof; and

a nitride semiconductor layer portion formed on a surface of both the depressed portion and the ridge portion and composed of a plurality of nitride semiconductor layers,

wherein part of the nitride semiconductor layer portion formed over a vicinity of at least one edge of the ridge portion protrudes from part of the nitride semiconductor layer portion formed over the ridge portion but elsewhere than in the vicinity of said edge.

2. The nitride semiconductor light-emitting device of claim 1,

wherein the part of the nitride semiconductor layer portion formed over the vicinity of said at least one edge of the ridge portion is thicker than the part of the nitride semiconductor layer portion formed over the ridge portion but elsewhere than in the vicinity of said edge.

3. The nitride semiconductor light-emitting device of claim 1, further comprising:

an inflow prevention wall, which is an elevated portion, formed at said at least one edge of the ridge portion,

wherein

the nitride semiconductor layer portion is formed over the inflow prevention wall, over the depressed portion, and over the ridge portion, and

part of the nitride semiconductor layer portion formed over the inflow prevention wall and part of the nitride semiconductor layer portion formed over the ridge portion form a continuous film.

4. The nitride semiconductor light-emitting device of claim 1,

wherein the nitride semiconductor layer portion has a light emission layer formed of InGaN.

5. The nitride semiconductor light-emitting device of claim 1,

wherein the depressed portion is not completely filled.

6. The nitride semiconductor light-emitting device of claim 1, further comprising:

an electrode pad formed on the nitride semiconductor layer portion and serving as where wire bonding is performed for external electrical connection,

wherein no part of the electrode pad is formed over the depressed portion.

7. The nitride semiconductor light-emitting device of claim 6,

wherein the electrode pad is formed 30 μ

m or more apart from an edge of the depressed portion.

8. The nitride semiconductor light-emitting device of claim 1,

wherein one device structure is formed in the ridge portion located between two adjacent ones of said depressed portion.

9. The nitride semiconductor light-emitting device of claim 1,

wherein a plurality of device structures are formed in the ridge portion located between two adjacent ones of said depressed portion.

10. The nitride semiconductor light-emitting device of claim 1,

wherein the device is split into an individual chip by scribing on a top surface of part of the nitride semiconductor layer portion formed over the depressed portion or on a bottom surface of part of the processed substrate directly under the depressed portion.

11. The nitride semiconductor light-emitting device of claim 1,

wherein the depressed portion has a depth of 1 μ

m or more but 20 μ

m or less.

12. The nitride semiconductor light-emitting device of claim 1,

wherein the depressed portion has an opening width of 1 μ

m or more.

13. The nitride semiconductor light-emitting device of claim 1,

wherein the ridge portion between adjacent ones of said depressed portion has a width of 140 μ

m or more but 4 mm or less.

14. The nitride semiconductor light-emitting device of claim 2,

wherein a level difference formed between the part of the nitride semiconductor layer portion formed over the vicinity of said at least one edge of the ridge portion and the part of the nitride semiconductor layer portion formed over the ridge portion but elsewhere than in the vicinity of said edge is 150 nm or more.

15. The nitride semiconductor light-emitting device of claim 2,

wherein part of the nitride semiconductor layer portion in contact with the surface of the processed substrate is a GaN layer with a thickness of 0.5 μ

m or less.

16. The nitride semiconductor light-emitting device of claim 2,

wherein part of the nitride semiconductor layer portion in contact with the surface of the processed substrate is an AlGaN layer.

17. The nitride semiconductor light-emitting device of claim 2,

wherein part of the nitride semiconductor layer portion in contact with the surface of the processed substrate is a GaN layer, and

the GaN layer is formed with a surface temperature of the processed substrate at 1,025°

C.

18. The nitride semiconductor light-emitting device of claim 2,

wherein part of the nitride semiconductor layer portion in contact with the surface of the processed substrate is a GaN layer, and

the GaN layer is formed with a ratio of a flow rate in mol per unit time of supply of a source material containing nitrogen atoms as a group V element to a flow rate in mol per unit time of supply of a source material containing Gallium atoms as a group III element at 2,000 or more.

19. The nitride semiconductor light-emitting device of claim 2,

wherein the nitride semiconductor layer portion includes an AlGaN layer with an Al composition ratio of 0.02 or more.

20. The nitride semiconductor light-emitting device of claim 3,

wherein the inflow prevention wall is formed of one of SiO₂, Al₂O₃, TiO₂, ZrO, and W.

21. The nitride semiconductor light-emitting device of claim 3,

wherein the inflow prevention wall has a thickness of 50 nm or more but 3 μ

m or less in a direction normal thereto, which is a direction perpendicular to a surface of the ridge portion.

22. The nitride semiconductor light-emitting device of claim 3,

wherein the inflow prevention wall has a width of 1 μ

m or more but 25 μ

m or less in a direction perpendicular to a length direction thereof.