NEAR UV LIGHT EMITTING DEVICE

• US 20130256630A1
• Filed: 03/29/2013
• Published: 10/03/2013
• Est. Priority Date: 03/29/2012
• Status: Active Grant

• Current Assignee: Seoul Viosys Co., Ltd. (Seoul Semiconductor Co., Ltd.)
• Original Assignee: Seoul Optodevice Company Limited (Seoul Semiconductor Co., Ltd.)
• Inventors: HAN, Chang Suk, KIM, Hwa Mok, CHOI, Hyo Shik, KO, Mi So, LEE, A Ram Cha
• Granted Patent: US 9,224,913 B2
• Time in Patent Office: Days
• US Class Current: 257/13
• CPC Class Codes: H01L 33/04 with a quantum effect structure or superlattice, e.g. tunnel junction
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01L 33/14 with a carrier transport control structure, e.g. highly-doped semiconductor layer or current-blocking structure
• CPC Class Codes: H01L 33/32 containing nitrogen

Abstract

Disclosed herein is an ultraviolet (UV) light emitting device. The light emitting device includes an n-type contact layer including a GaN layer; a p-type contact layer including a GaN layer; and an active layer of a multi-quantum well structure disposed between the n-type contact layer and the p-type contact layer, the active area configured to emit near ultraviolet light at wavelengths of 365 nm to 309 nm.

Claims

1. A light emitting device, comprising:

an n-type contact layer comprising a GaN layer;

a p-type contact layer comprising a GaN layer; and

an active area comprising a multi-quantum well structure disposed between the n-type contact layer and the p-type contact layer, the active area configured to emit near ultraviolet light at wavelengths of 365 nm to 309 nm.

2. The light emitting device of claim 1, wherein the active area of the multi-quantum well structure comprises barrier layers and well layers, the barrier layers comprising AlGaN, and a first barrier layer closest to the n-type contact layer containing 2% to 4% more Al than the other barrier layers.

3. The light emitting device of claim 2, wherein:

the well layers comprise InGaN and emit near ultraviolet light at wavelengths of 375 nm to 390 nm; and

the barrier layers except for the first barrier layer comprise AlInGaN comprising 15% to 25% of Al and 1% or less of In.

4. The light emitting device of claim 3, wherein the first barrier layer comprises AlInGaN comprising 30% to 40% of Al and 1% or less of In.

5. The light emitting device of claim 1, wherein the p-type contact layer comprises:

a first high-density doping layer;

a second high-density doping layer; and

a low-density doping layer disposed between the first high-density doping layer and the second high-density doping layer.

6. The light emitting device of claim 5, wherein the low-density doping layer is thicker than the first and second high-density doping layers.

7. The light emitting device of claim 1, wherein the n-type contact layer comprises:

a first GaN layer;

a second GaN layer; and

an intermediate layer comprising a multilayer structure and disposed between the first and second GaN layers.

8. The light emitting device of claim 7, wherein the intermediate layer comprises alternately stacked AlInN and GaN layers.

9. The light emitting device of claim 1, further comprising:

a superlattice layer disposed between the n-type contact layer and the active area; and

an electron implantation layer disposed between the superlattice layer and the active area, the electron implantation layer comprising a higher n-type impurity doping density than the superlattice layer.

10. The light emitting device of claim 9, wherein the superlattice layer comprises a sequentially stacked InGaN/InGaN structure, and the electron implantation layer comprises GaN or InGaN.

11. The light emitting device of claim 9, further comprising an undoped GaN layer disposed between the n-type contact layer and the superlattice layer.

12. The light emitting device of claim 11, further comprising:

a low-density GaN layer disposed between the undoped GaN layer and the superlattice layer, the low-density GaN layer being doped with an n-type impurity at a lower density than the n-type contact layer; and

a high-density GaN layer disposed between the low-density GaN layer and the superlattice layer, the high-density GaN layer being doped with an n-type impurity at a higher density than the low-density GaN layer.