# US 9,520,535 B2 · Light emitting device and lighting system

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- Number: US 9,520,535 B2
- Document ID: US9520535B2
- Status: Granted
- Kind: B2
- Application number: 14/829,830
- Filed: 2015-08-19
- Published: 2016-02-25
- Granted: 2016-12-13
- Earliest claimed: 2014-08-20
- Assignees: LG Innotek Co., Ltd.
- Applicants: LG Innotek Co., Ltd.
- Inventors: Chan Keun Park; Hyeong Jun Kim; Myung Hoon Jung; Jae Woong Han
- Web page: https://patentgrep.com/patent/US9520535B2

## CPC

- H10H 20/8252: {characterised by the dopants}
- H10H 20/811: having quantum effect structures or superlattices, e.g. tunnel junctions
- H10H 20/812: within the light-emitting regions, e.g. having quantum confinement structures
- H10H 20/8215: {characterised by crystalline imperfections, e.g. dislocations; characterised by the distribution of dopants, e.g. delta-doping}
- H10H 20/824: comprising only Group III-V materials, e.g. GaP
- H10H 20/815: having stress relaxation structures, e.g. buffer layers
- H10H 20/825: containing nitrogen, e.g. GaN
- H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS

## Abstract

A light emitting device includes a first electrode, a first semiconductor layer disposed on the first electrode and including a first conductive dopant, a second semiconductor layer disposed on the first semiconductor layer and including the first conductive dopant having a doping concentration lower than a doping concentration of the first semiconductor layer, a third semiconductor layer disposed on the second semiconductor layer to adjust stress, a first conductive semiconductor layer on the third semiconductor layer, an active layer on the first conductive semiconductor layer, a second conductive semiconductor layer on the active layer; and a second electrode on the second conductive semiconductor layer, the third semiconductor layer has a doping concentration in a range between the doping concentration of the second semiconductor layer and a doping concentration of the first conductive semiconductor layer, and the doping concentration of the third semiconductor layer is increased toward the first conductive semiconductor layer.

## Claims

### Claim 1

A light emitting device comprising:
a first electrode;
a first semiconductor layer disposed on the first electrode and including a first conductive dopant;
a second semiconductor layer disposed on the first semiconductor layer and including the first conductive dopant having a doping concentration lower than a doping concentration of the first semiconductor layer;
a third semiconductor layer disposed on the second semiconductor layer to adjust stress;
a first conductive semiconductor layer on the third semiconductor layer;
an active layer on the first conductive semiconductor layer;
a second conductive semiconductor layer on the active layer; and
a second electrode on the second conductive semiconductor layer,
wherein the third semiconductor layer has a doping concentration in a range between the doping concentration of the second semiconductor layer and a doping concentration of the first conductive semiconductor layer, and the doping concentration of the third semiconductor layer is increased toward the first conductive semiconductor layer, and
wherein the first conductive semiconductor layer includes the first conductive dopant having a doping concentration higher than a doping concentration of the second semiconductor layer and the third semiconductor layer.

### Claim 2 (depends on 1)

The light emitting device of claim 1, wherein the first semiconductor layer comprises a superlattice layer formed by repeatedly stacking GaN and AlyGa(1-y)(0≦y≦1).

### Claim 3 (depends on 2)

The light emitting device of claim 2, wherein the first semiconductor layer further comprises a last layer, and the last layer includes GaN.

### Claim 4 (depends on 3)

The light emitting device of claim 3, wherein the last layer has a thickness in a range of 20 nm to 100 nm.

### Claim 5 (depends on 1)

The light emitting device of claim 1, wherein the second semiconductor layer comprises AlyGa(1-y)N (0≦y≦1).

### Claim 6 (depends on 1)

The light emitting device of claim 1, wherein the second semiconductor layer has a thickness in a range of 5 nm to 100 nm.

### Claim 7 (depends on 1)

The light emitting device of claim 1, wherein a rate of change in the doping concentration of the third semiconductor layer is constant.

### Claim 8 (depends on 1)

The light emitting device of claim 1, wherein the doping concentration of the third semiconductor layer is changed stepwise.

### Claim 9 (depends on 1)

The light emitting device of claim 1, wherein a rate of change in the doping concentration of the third semiconductor layer is gradually decreased from a lower portion of the third semiconductor layer to an upper portion of the third semiconductor layer.

### Claim 10

A light emitting device comprising:
a first conductive semiconductor layer;
an active layer on the first conductive semiconductor layer;
an AlpGaqIn1-p-qN layer (0<p≦1 and 0≦q≦1) on the active layer;
an undoped AlrGa1-rN layer (0<r<1) or an undoped AltGa1-tN layer (0≦t<1) on the AlpGaqIn1-p-qN layer (0<p≦1 and 0≦q≦1);
a second conductive semiconductor layer on the undoped AlrGa1-rN layer (0<r<1) or the undoped AltGa1-tN layer (0≦t<1); and
a P type AlsGa1-sN layer (0<s<1) disposed between the AlpGaqIn1-p-qN layer (0<p≦1 and 0≦q≦1) and the second conductive semiconductor layer.

### Claim 11 (depends on 10)

The light emitting device of claim 10, wherein the second conductive semiconductor layer comprises:
a first concentration-second conductive semiconductor layer having a first concentration; and
a second concentration-second conductive semiconductor layer formed on the first concentration-second conductive semiconductor layer and having a second concentration higher than the first concentration.

### Claim 12 (depends on 10)

The light emitting device of claim 10, wherein the undoped AlrGa1-rN layer (0<r<1) or the undoped AltGa1-tN layer (0≦t<1) comprises an undoped GaN layer.

### Claim 13 (depends on 12)

The light emitting device of claim 12, wherein the second conductive semiconductor layer comprises:
a first concentration-P type GaN layer having a first concentration on the undoped GaN layer; and
a second concentration-P type GaN layer formed on the first concentration-P type GaN layer and having a second concentration higher than the first concentration.

### Claim 14 (depends on 10)

The light emitting device of claim 10, wherein the undoped AltGa1-tN layer comprises an undoped AlGaN based layer.

### Claim 15 (depends on 14)

The light emitting device of claim 14, wherein the second conductive semiconductor layer comprises:
a first concentration-P type AlGaN based layer having a first concentration on the undoped AlGaN based layer; and
a second concentration-P type AlGaN based layer formed on the first concentration-P type AlGaN based layer and having a second concentration higher than the first concentration.

### Claim 16 (depends on 10)

The light emitting device of claim 10, wherein the AlpGaqIn1-p-qN layer (0<p≦1 and 0≦q≦1) has a thickness in a range of 10 nm to 50 nm.

### Claim 17 (depends on 10)

The light emitting device of claim 10, wherein the P type AlsGa1-sN layer (0<s<1) or the AlpGaqIn1-p-qN layer (0<p≦1 and 0≦q≦1) has a thickness in a range of 1 nm to 3 nm.

### Claim 18 (depends on 10)

The light emitting device of claim 10, wherein one to five pairs of undoped AlrGa1-rN layers (0<r<1) and P type AlsGa1-sN layers (0<s<1) are provided.

### Claim 19 (depends on 10)

The light emitting device of claim 10, wherein an aluminum concentration (r) in the undoped AlrGa1-rN layer (0<r<1) is in a range of 0.04≦r≦0.15.

### Claim 20 (depends on 10)

The light emitting device of claim 10, wherein an aluminum concentration (s) of the P type AlsGa1-sN layer (0<s<1) is in a range of 0.20≦s≦0.35.