Nitride semiconductor light emitting device

• US 20060038166A1
• Filed: 08/18/2005
• Published: 02/23/2006
• Est. Priority Date: 08/19/2004
• Status: Active Grant

• Current Assignee: Sharp Fukuyama Laser Co., Ltd. (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Kamikawa, Takeshi, Tsuda, Yuhzoh
• Granted Patent: US 7,709,858 B2
• Time in Patent Office: Days
• US Class Current: 257/13
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01L 33/007 comprising nitride compounds
• CPC Class Codes: H01S 2304/12 Pendeo epitaxial lateral overgrowth [ELOG], e.g. for growing GaN based blue laser diodes
• CPC Class Codes: H01S 5/0207 Substrates having a special shape
• CPC Class Codes: H01S 5/2201 in a specific crystallographic orientation
• CPC Class Codes: H01S 5/320275 semi-polar orientation
• CPC Class Codes: H01S 5/34333 with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser

Abstract

A first region and a second region that has a defect density of which the value is higher than that of the first region are respectively formed so as to be aligned in stripe form in the direction parallel to the direction in which a dug out region extends, where atoms that terminate the surface of the first region are different from atoms that terminate the surface of the aforementioned second region, and the dug out region includes the first region and the second region.

Claims

1. A nitride semiconductor light emitting device comprising:

a processed substrate where a dug out region which is a recess in stripe form and a hill which is a protrusion are provided in a surface of a nitride semiconductor substrate where at least the surface is formed of a nitride semiconductor; and

a nitride semiconductor growth layer which is formed of a plurality of nitride semiconductor thin films layered on the surface of the processed substrate, wherein

a first region having a first average defect density and a second region having a defect density of which the value is higher than that of the first average defect density are respectively formed so as to be aligned in stripe form in the direction parallel to the direction in which the dug out region extends in the processed substrate,

atoms that terminate the surface of the first region and atoms that terminate the surface of the second region are different from each other, and

in the processed substrate before the nitride semiconductor growth layer is layered, the dug out region includes the second region in a manner where the first region and the second region are both exposed from the bottom of the dug out region and the second region is not exposed from the portions other than the bottom in the dug out region.

2. The nitride semiconductor light emitting device according to claim 1, wherein

the value of the width of the opening of the dug out region is greater than that of the depth of the dug out region.

3. The nitride semiconductor light emitting device according to claim 1, wherein

the dug out region is not completely filled in with the nitride semiconductor growth layer.

4. The nitride semiconductor light emitting device according to claim 1, wherein

atoms that terminate the surface of the second region are nitrogen.

5. The nitride semiconductor light emitting device according to claim 1, wherein

atoms that terminate the surface of the first region are gallium.

6. The nitride semiconductor light emitting device according to claim 1, wherein

the off angle of the upper surface of the nitride semiconductor substrate is in a range between 0.15°

and 0.5°

, both ends inclusive.

7. The nitride semiconductor light emitting device according to claim 1, wherein

the width of the opening of the dug out region is in a range between 20 μ

m and 100 μ

m, both ends inclusive.

8. The nitride semiconductor light emitting device according to claim 1, wherein

the depth of the dug out region is in a range between 3 μ

m and 10 μ

m, both ends inclusive.

9. The nitride semiconductor light emitting device according to claim 1, wherein

the width of the second region in the direction perpendicular to the direction in which the second region extends in stripe form is in a range between 15 μ

m and 50 μ

m, both ends inclusive.

10. The nitride semiconductor light emitting device according to claim 1, wherein

the gap between the boundary between the first region and the second region on the surface of the bottom and the side of the dug out region that is adjacent to the boundary is 2 μ

m or more within the dug out region.

11. The nitride semiconductor light emitting device according to claim 1, wherein

the width of the hill is 400 μ

m or more.

12. The nitride semiconductor light emitting device according to claim 1, wherein

the thickness of the nitride semiconductor growth layer is 5 μ

m or less.

13. The nitride semiconductor light emitting device according to claim 1, wherein

the layer of the nitride semiconductor growth layer layered on the processed substrate which makes contact with the processed substrate is a multilayered film formed of an Al_xGa₁₋

xN layer and an Al_yGa<sub>1−

y</sub>N layer of which the Al component ratios are different, and

the relationship between the Al component ratio x of the Al_xGa<sub>1−

x</sub>N layer and the Al component ratio y of the Al_yGa<sub>1−

y</sub>N layer satisfies 0<

x≦

0.3, 0<

y≦

0.1 and x<

y.

14. The nitride semiconductor light emitting device according to claim 13, wherein

the thicknesses of the Al_xGa₁₋

xN layer and the Al_yGa<sub>1−

y</sub>N layer that form the multilayered film are both in a range between 80 nm and 3 μ

m, both ends inclusive.

15. The nitride semiconductor light emitting device according to claim 13, wherein

the thickness of the Al_yGa₁₋

yN layer of which the Al component ratio is large is thinner than the thickness of the Al_xGa<sub>1−

x</sub>N layer of which the Al component ratio is small.

16. The nitride semiconductor light emitting device according to claim 13, wherein

the nitride semiconductor thin film that forms the topmost surface of the multilayered film is the Al_xGa₁₋

xN layer of which the Al component ratio is small.

17. The nitride semiconductor light emitting device according to claim 1, wherein

a ridge stripe for narrowing a current is formed in a portion of the first region other than the dug out region on the surface of the nitride semiconductor growth layer, and

when the distance between the center portion of the ridge stripe and the center portion of the hill is denoted as d and the gap between the center portions of the two adjacent dug out regions in the direction perpendicular to the direction in which the dug out regions extends is denoted as A, 3 μ

m≦

d≦

0.25×

A is achieved.