NITRIDE SEMICONDUCTOR LIGHT-EMITTING DIODE

• US 20140353699A1
• Filed: 06/02/2014
• Published: 12/04/2014
• Est. Priority Date: 06/03/2013
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: FUJITA, TOSHIYUKI, YOKOGAWA, TOSHIYA, INOUE, AKIRA
• Granted Patent: US 9,276,171 B2
• Time in Patent Office: Days
• US Class Current: 257/94
• CPC Class Codes: H01L 33/0095 Post-treatment of devices, e.g. annealing, recrystallisation or short-circuit elimination
• CPC Class Codes: H01L 33/16 with a particular crystal structure or orientation, e.g. polycrystalline, amorphous or porous
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate

Abstract

Provided is a nitride semiconductor light-emitting diode having a higher light extraction efficiency and a higher polarization degree. A nitride semiconductor light-emitting diode according to the present invention comprises an active layer generating a polarized light, a first side surface, a second side surface, a third side surface, and a fourth side surface. The first and second side surfaces consist only of a plane including the Z-axis and the Y-axis. The third and fourth side surfaces are perpendicular to the first and second side surfaces and include the X-axis. The third and fourth side surfaces include an inclined surface.

Claims

1. A nitride semiconductor light-emitting diode, comprising:

an n-side electrode;

a p-side electrode;

a nitride semiconductor stacking structure formed of a plurality of nitride semiconductor layers each having a principal surface of a non-polar plane or a semi-polar plane;

an active layer which is included in the nitride semiconductor stacking structure and generates a polarized light;

a first side surface;

a second side surface;

a third side surface; and

a fourth side surface, wherein

X-axis is parallel to a polarization direction of the polarized light;

Z-axis is parallel to a normal direction of the principal surface;

Y-axis is perpendicular to both of the X-axis and the Z-axis;

the nitride semiconductor light-emitting diode comprises a light extraction surface through which the polarized light is emitted toward the outside of the nitride semiconductor light-emitting diode;

the light extraction surface has a normal line parallel to the Z-axis;

the first side surface consists only of a plane including the Z-axis and the Y-axis;

the second side surface consists only of a plane including the Z-axis and the Y-axis;

the second side surface is disposed parallel to the first side surface (150a);

the third side surface is perpendicular to the first and second side surfaces and includes the X-axis;

the fourth side surface is perpendicular to the first and second side surfaces and includes the X-axis;

the third side surface includes an inclined surface;

the fourth side surface includes an inclined surface;

the third and fourth side surfaces are symmetric with respect to a plane which includes the Z-axis and the X-axis; and

the following mathematical formulae (I), (II), and (III) are satisfied;

15 degrees≦

θ

≦

70 degrees 

 

(I)

0.1≦

(L3 cos θ

)/h1≦

0.5 

 

(II)

L2<

L1 

 

(III)

where

θ

represents an angle formed between the inclined surface and the Z-axis in a cross-sectional view including the Z-axis and the Y-axis;

h1 represents a height of the nitride semiconductor light-emitting diode in the cross-section;

L1 represents a width of the nitride semiconductor light-emitting diode in the cross-section;

L2 represents a width of the light extraction surface in the cross-section; and

L3 represents a length of the inclined surface in the cross-section.

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

θ

is not less than 20 degrees and not more than 50 degrees.

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

θ

is not less than 28 degrees and not more than 45 degrees.

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

the value of (L3 cos θ

) is not less than 0.20 and not more than 0.40.

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

the value of (L3 cos θ

) is not less than 0.26 and not more than 0.37.

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

the X axis, the Y-axis, and the Z-axis are an A-axis, a C-axis, and an M-axis, respectively,

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

each of the third and fourth side surfaces comprises a vertical surface which includes the Z-axis and the X-axis.

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

the light extraction surface is flat.