SEMICONDUCTOR LIGHT EMITTING DEVICE AND METHOD FOR MANUFACTURING SEMICONDUCTOR LIGHT EMITTING DEVICE

• US 20140183446A1
• Filed: 12/02/2013
• Published: 07/03/2014
• Est. Priority Date: 12/27/2012
• Status: Active Grant

• Current Assignee: Seoul Semiconductor Co., Ltd.
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: NAGO, Hajime, KIMURA, Shigeya, NUNOUE, Shinya, HARADA, Yoshiyuki, YOSHIDA, Hisashi
• Granted Patent: US 9,112,111 B2
• Time in Patent Office: Days
• US Class Current: 257/13
• CPC Class Codes: H01L 33/0025 comprising only AIIIBV compounds
• CPC Class Codes: H01L 33/007 comprising nitride compounds
• CPC Class Codes: H01L 33/0075 comprising nitride compounds
• CPC Class Codes: H01L 33/02 characterised by the semiconductor bodies
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01L 33/325 characterised by the doping materials
• CPC Class Codes: H01S 5/3013 AIIIBV compounds
• CPC Class Codes: H01S 5/305 characterised by the doping materials used in the laser structure
• CPC Class Codes: H01S 5/3063 using Mg
• CPC Class Codes: H01S 5/3206 ordering or disordering the natural superlattice in ternary or quaternary materials
• CPC Class Codes: H01S 5/3216 quantum well or superlattice cladding layers
• CPC Class Codes: H01S 5/34333 with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser

Abstract

According to one embodiment, a semiconductor light emitting device includes an n-type semiconductor layer, a p-type semiconductor layer, and a light emitting layer. The p-type semiconductor layer includes a first p-side layer, a second p-side layer, and a third p-side layer. A concentration profile of Mg of a p-side region includes a first portion, a second portion, a third portion, a fourth portion, a fifth portion, a sixth portion and a seventh portion. The p-side region includes the light emitting layer, the second p-side layer, and the third p-side layer. A Mg concentration of the sixth portion is not less than 1×10²⁰ cm⁻³ and not more than 3×10²⁰ cm⁻³. The Al concentration is 1/100 of the maximum value at a second position. A Mg concentration at the second position is not less than 2×10¹⁸ cm⁻³.

Claims

1. A semiconductor light emitting device, comprising:

an n-type semiconductor layer including a nitride semiconductor;

a p-type semiconductor layer including a first p-side layer, a second p-side layer of Al_x2Ga_1-x2N (0.05≦

x2≦

0.2), and a third p-side layer of Al_x3Ga_1-x3N (0≦

x3≦

x2), the first p-side layer including a nitride semiconductor including Mg, the second p-side layer being provided between the first p-side layer and the n-type semiconductor layer and including Mg, the third p-side layer being provided between the first p-side layer and the second p-side layer and including Mg; and

a light emitting layer provided between the n-type semiconductor layer and the second p-side layer, the light emitting layer including a nitride semiconductor,

a concentration profile of Mg of a p-side region including the light emitting layer, the second p-side layer, and the third p-side layer including;

a first portion;

a second portion provided between the first portion and the first p-side layer;

a third portion provided between the first portion and the second portion, a Mg concentration of the third portion increasing at a first increase rate along a first direction from the n-type semiconductor layer toward the first p-side layer;

a fourth portion provided between the third portion and the second portion, a Mg concentration of the fourth portion increasing at a second increase rate along the first direction;

a fifth portion provided between the third portion and the fourth portion, a Mg concentration of the fifth portion increasing at a third increase rate along the first direction, the third increase rate being lower than the first increase rate and lower than the second increase rate;

a sixth portion provided between the fourth portion and the second portion, a Mg concentration of the sixth portion being not less than 1×

10²⁰ cm<sup>−

3</sup> and not more than 3×

10²⁰ cm<sup>−

3</sup> and being higher than the concentrations of Mg of the first portion, the second portion, the third portion, the fourth portion, and the fifth portion; and

a seventh portion provided between the sixth portion and the second portion, a Mg concentration of the seventh portion decreasing along the first direction,

an Al concentration in the p-side region having a maximum value at a first position,

the Al concentration being 1/100 of the maximum value at a second position arranged with the first position along the first direction in a region between the first position and a position corresponding to the first portion,

a Mg concentration at the second position being not less than 2×

10¹⁸ cm<sup>−

3</sup>.

2. The device according to claim 1, wherein a peak wavelength of light emitted from the light emitting layer is not less than 400 nm and not more than 650 nm.

3. The device according to claim 1, wherein a peak wavelength of light emitted from the light emitting layer is not less than 430 nm and not more than 460 nm.

4. The device according to claim 1, wherein the Mg concentration at the second position is not more than 1.2×

10¹⁹ cm<sup>−

3</sup>.

5. The device according to claim 1, wherein the Mg concentration of the fifth portion is not less than 1×

10¹⁹ cm<sup>−

3</sup> and not more than 3×

10¹⁹ cm<sup>−

3</sup>.

6. The device according to claim 1, wherein a concentration of C (carbon) in the p-side region is not more than 5×

10¹⁸ cm<sup>−

3</sup>.

7. The device according to claim 1, wherein a length of the fifth portion along the first direction is shorter than a length of the third portion along the first direction and shorter than a length of the fourth portion along the first direction.

8. The device according to claim 1, wherein a length of the third portion along the first direction is not less than 5 nm and not more than 30 nm.

9. The device according to claim 1, wherein a length of the fourth portion along the first direction is not less than 5 nm and not more than 30 nm.

10. The device according to claim 1, wherein a length of the fifth portion along the first direction is not less than 3 nm and not more than 20 nm.

11. The device according to claim 1, wherein a distance along the first direction between the first position and the second position is not less than 5 nm and not more than 30 nm.

12. The device according to claim 1, wherein

the light emitting layer includes a plurality of barrier layers and a well layer provided between the plurality of barrier layers,

the barrier layer includes In_y1Ga_1-y1N (0≦

y1<

1),

the well layer includes In_y2Ga_1-y2N (0<

y2≦

1 and y1<

y2), and

y1 is smaller than y2.

13. The device according to claim 12, wherein

an In concentration in the p-side region has a maximum value at a third position,

the In concentration is 1/10 of the maximum value at a fourth position arranged with the third position along the first direction in a region between the third position and a position corresponding to the second portion, and

a Mg concentration at the fourth position is not less than 3×

10¹⁹ cm<sup>−

3</sup>.

14. The device according to claim 13, wherein the Mg concentration at the fourth position is not more than 8×

10¹⁹ cm<sup>−

3</sup>.

15. The device according to claim 1, wherein the second position is positioned inside the third portion.

16. The device according to claim 1, wherein the second position is positioned inside the fifth portion.

17. The device according to claim 1, wherein the second position is positioned inside the fourth portion.

18. A method for manufacturing a semiconductor light emitting device, comprising:

forming a light emitting layer including a nitride semiconductor on an n-type semiconductor layer including a nitride semiconductor;

forming a first film of Al_xGa_1-xN (0.05≦

x≦

0.2) on the light emitting layer, the first film including Mg;

forming a second film including a nitride semiconductor including Mg on the first film; and

forming a third film including a nitride semiconductor including Mg on the second film,

the forming of the first film including alternately and multiply repeating;

a first process of supplying a group V source-material gas, a gas including Ga, a gas including Al, and a gas including Mg; and

a second process of supplying the group V source-material gas without supplying the gas including Ga, the gas including Al, and the gas including Mg,

a maximum value of a concentration of Mg in a p-side region including the light emitting layer, the first film, and the second film being not less than 1×

10²⁰ cm<sup>−

3</sup> and not more than 3×

10²⁰ cm<sup>−

3</sup>,

an Al concentration in the p-side region having a maximum value at a first position,

the Al concentration being 1/100 of the maximum value at a second position arranged with the first position along a first direction from the light emitting layer toward the first film in a region between the first position and a position corresponding to the light emitting layer,

a Mg concentration at the second position being not less than 2×

10¹⁸ cm<sup>−

3</sup>.

19. The method according to claim 18, wherein a concentration profile of Mg in the p-side region includes:

a first portion;

a second portion provided between the first portion and the third film;

a third portion provided between the first portion and the second portion, a Mg concentration of the third portion increasing at a first increase rate along the first direction;

a fourth portion provided between the third portion and the second portion, a Mg concentration of the fourth portion increasing at a second increase rate along the first direction;

a fifth portion provided between the third portion and the fourth portion, a Mg concentration of the fifth portion increasing at a third increase rate along the first direction, the third increase rate being lower than the first increase rate and lower than the second increase rate;

a sixth portion provided between the fourth portion and the second portion, a Mg concentration of the sixth portion being not less than 1×

10²⁰ cm<sup>−

3</sup> and not more than 3×

10²⁰ cm<sup>−

3</sup> and being higher than the concentrations of Mg of the first portion, the second portion, the third portion, the fourth portion, and the fifth portion; and

a seventh portion provided between the sixth portion and the second portion, a Mg concentration of the seventh portion decreasing along the first direction.

20. The method according to claim 18, wherein a concentration of C (carbon) in the p-side region is not more than 5×

10¹⁸ cm<sup>−

3</sup>.