SEMICONDUCTOR LIGHT EMITTING ELEMENT

• US 20120199861A1
• Filed: 02/08/2012
• Published: 08/09/2012
• Est. Priority Date: 02/09/2011
• Status: Active Grant

• Current Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Original Assignee: Showa Denko KK (Resonac Holdings Corp.)
• Inventors: TSUJI, Yukie
• Granted Patent: US 8,637,886 B2
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: H01L 2224/14 of a plurality of bump connectors
• CPC Class Codes: H01L 33/38 with a particular shape
• CPC Class Codes: H01L 33/405 Reflective materials
• CPC Class Codes: H01L 33/42 Transparent materials
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating

Abstract

A semiconductor light emitting element includes: a light emitting layer and a p-type semiconductor layer laminated on an n-type semiconductor layer; a transparent conductive layer laminated on the p-type semiconductor layer; a transparent insulating layer laminated on the transparent conductive layer and the exposed n-type semiconductor layer, the transparent insulating layer having plural tapered through-holes formed therein; a p-electrode formed on the transparent conductive layer with the transparent insulating layer interposed therebetween, the p-electrode being connected to the transparent conductive layer via the through-holes provided for the transparent insulating layer; and an n-electrode formed on the n-type semiconductor layer with the transparent insulating layer interposed therebetween, the n-electrode being connected to the n-type semiconductor layer via the through-holes provided for the transparent insulating layer.

Claims

1. A semiconductor light emitting element comprising:

a first semiconductor layer composed of a III-V semiconductor having a first conductivity type;

a light emitting layer provided on the first semiconductor layer so as to be in contact with the first semiconductor layer, the light emitting layer being composed of a III-V semiconductor and emitting light by being energized;

a second semiconductor layer provided on the light emitting layer so as to be in contact with the light emitting layer, the second semiconductor layer being composed of a III-V semiconductor having a second conductivity type opposite to the first conductivity type;

a transparent conductive layer composed of a material that is conductive and transparent to light outputted from the light emitting layer, the transparent conductive layer being laminated on the second semiconductor layer;

a transparent insulating layer composed of a material that is insulative and transparent to light outputted from the light emitting layer, the transparent insulating layer having a through-hole penetrating therethrough in the thickness direction, the transparent insulating layer being laminated on the transparent conductive layer;

a first electrode connected to the first semiconductor layer, the first electrode serving as one terminal to energize the light emitting layer; and

a second electrode laminated on the transparent insulating layer, the second electrode being connected to the transparent conductive layer via the through-hole provided for the transparent insulating layer, the second electrode serving as the other terminal to energize the light emitting layer, wherein

a contact surface of the transparent insulating layer with the transparent conductive layer and an inner wall surface of the through-hole provided for the transparent insulating layer form an acute angle.

2. The semiconductor light emitting element according to claim 1, wherein a surface of the transparent insulating layer opposite to the contact surface and the inner wall surface of the through-hole provided for the transparent insulating layer form an obtuse angle.

3. The semiconductor light emitting element according to claim 1, wherein the through-hole formed in the transparent insulating layer has a shape whose width increases from a side close to the transparent conductive layer toward a side far therefrom.

4. The semiconductor light emitting element according to claim 1, wherein the through-hole formed in the transparent insulating layer is substantially circular, and has a shape whose diameter increases from a side close to the transparent conductive layer toward a side far therefrom.

5. The semiconductor light emitting element according to claim 1, wherein the contact surface of the transparent insulating layer and the inner wall surface of the through-hole provided for the transparent insulating layer form an angle from 15 degrees to 60 degrees.

6. The semiconductor light emitting element according to claim 1, wherein the transparent insulating layer has a plurality of the through-holes formed therein.

7. The semiconductor light emitting element according to claim 1, wherein the second electrode includes:

a first coating layer having conductivity and provided to cover the transparent insulating layer and the transparent conductive layer that is exposed via the through-hole;

a metal reflection layer composed of a metal material that is conductive and reflective to light outputted from the light emitting layer, the metal reflection layer being provided on the first coating layer so as to be in contact with the first coating layer;

a second coating layer provided to cover the metal reflection layer; and

a connecting layer provided on the second coating layer so as to be in contact with the second coating layer, the connecting layer being used for electrical connection with outside.

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

the transparent conductive layer is composed of a material that exhibits a first refractive index at a wavelength of light the light emitting layer outputs, and

the transparent insulating layer is composed of a material that exhibits a second refractive index at a wavelength of light the light emitting layer outputs, the second refractive index being smaller than the first refractive index.

9. The semiconductor light emitting element according to claim 1, wherein the III-V semiconductor is made of a group III nitride semiconductor.

10. The semiconductor light emitting element according to claim 1, wherein the first electrode and the second electrode are respectively mounted with solder bumps that are used for electrical connection with outside.

11. A semiconductor light emitting element comprising:

a first semiconductor layer composed of a III-V semiconductor having a first conductivity type;

a light emitting layer provided on the first semiconductor layer so as to be in contact with the first semiconductor layer, the light emitting layer being composed of a III-V semiconductor and emitting light by being energized;

a second semiconductor layer provided on the light emitting layer so as to be in contact with the light emitting layer, the second semiconductor layer being composed of a III-V semiconductor having a second conductivity type opposite to the first conductivity type;

a transparent conductive layer composed of a material that is conductive and transparent to light outputted from the light emitting layer, the transparent conductive layer being laminated on the second semiconductor layer;

a transparent insulating layer composed of a material that is insulative and transparent to light outputted from the light emitting layer, the transparent insulating layer being laminated on the transparent conductive layer, the transparent insulating layer having a plurality of through-holes that penetrate therethrough in the thickness direction and have diameters decreasing toward the transparent conductive layer;

a first electrode connected to the first semiconductor layer, the first electrode serving as one terminal to energize the light emitting layer; and

a second electrode including

a conductor portion having a plurality of connecting conductors that respectively have one ends connected to the transparent conductive layer via the plurality of through-holes and are respectively provided along inner wall surfaces in the plurality of through-holes, and

an electrode portion provided on the transparent insulating layer so as to be in contact with the transparent insulating layer, the electrode portion being electrically connected with the other ends of the plurality of connecting conductors composing the conductor portion, the second electrode serving as the other terminal to energize the light emitting layer.

12. The semiconductor light emitting element according to claim 11, wherein the second electrode includes:

a first coating layer having conductivity and provided to cover the transparent insulating layer and the transparent conductive layer that is exposed via the through-holes;

a metal reflection layer composed of a metal material that is conductive and reflective to light outputted from the light emitting layer, the metal reflection layer being provided on the first coating layer so as to be in contact with the first coating layer;

a second coating layer provided to cover the metal reflection layer; and

a connecting layer provided on the second coating layer so as to be in contact with the second coating layer, the connecting layer being used for electrical connection with outside.

13. The semiconductor light emitting element according to claim 12, wherein

the transparent conductive layer is composed of an oxide containing indium (In),

the metal reflection layer is composed of a metal containing silver (Ag), and

the connecting layer is composed of a metal containing gold (Au).

14. The semiconductor light emitting element according to claim 11, wherein

the transparent conductive layer is composed of a material that exhibits a first refractive index at a wavelength of light the light emitting layer outputs, and

the transparent insulating layer is composed of a material that exhibits a second refractive index at a wavelength of light the light emitting layer outputs, the second refractive index being smaller than the first refractive index.

15. The semiconductor light emitting element according to claim 11, wherein the III-V semiconductor is made of a group III nitride semiconductor.

16. The semiconductor light emitting element according to claim 11, wherein the first electrode and the second electrode are respectively mounted with solder bumps that are used for electrical connection with outside.