Nitride semiconductor; light-emitting device, light-emitting diode, laser device and lamp using the semiconductor; and production methods thereof

• US 7,488,971 B2
• Filed: 10/01/2004
• Issued: 02/10/2009
• Est. Priority Date: 10/02/2003
• Status: Active Grant

• Current Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Original Assignee: Showa Denko KK (Resonac Holdings Corp.)
• Inventors: Kobayakawa, Masato, Okuyama, Mineo, Tomozawa, Hideki
• Primary Examiner(s): Valentine; Jami M
• Application Number:
  US10/574,202
• Publication Number:
  US 20070012932A1
• Time in Patent Office: 1,593 Days
• Field of Search: 257/13, 257/79, 257/94, 438/22
• US Class Current: 257/13
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01L 21/0237 Materials
• CPC Class Codes: H01L 21/0242 Crystalline insulating materials
• CPC Class Codes: H01L 21/02458 Nitrides
• CPC Class Codes: H01L 21/02488 Insulating materials
• CPC Class Codes: H01L 21/02505 consisting of more than two layers
• CPC Class Codes: H01L 21/0254 Nitrides
• CPC Class Codes: H01L 21/02576 N-type
• CPC Class Codes: H01L 21/02579 P-type
• CPC Class Codes: H01L 21/0262 Reduction or decomposition of gaseous compounds, e.g. CVD
• CPC Class Codes: H01L 33/007 comprising nitride compounds
• CPC Class Codes: H01L 33/0075 comprising nitride compounds
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/325 characterised by the doping materials
• CPC Class Codes: H01S 2304/04 MOCVD or MOVPE
• CPC Class Codes: H01S 5/3086 doping of the active layer
• CPC Class Codes: H01S 5/3407 characterised by special barrier 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

A nitride semiconductor product including an n-type layer, a light-emitting layer, and a p-type layer which are formed of a nitride semiconductor and sequentially stacked on a substrate in the above order, the light-emitting layer having a quantum well structure in which a well layer is sandwiched by barrier layers having band gaps wider than the band gap of the well layer. Each barrier layer includes a barrier sublayer C which has been grown at a temperature higher than a growth temperature of the well layer, and a barrier sublayer E which has been grown at a temperature lower than a growth temperature of the barrier sublayer C. The barrier sublayer C is disposed closer to the substrate with respect to the barrier sublayer E.

Claims

1. A nitride semiconductor product comprising an n-type layer, a light-emitting layer, and a p-type layer which are formed of a nitride semiconductor and sequentially stacked on a substrate in the above order,

said light-emitting layer having a quantum well structure in which a well layer is sandwiched by barrier layers having band gaps wider than the band gap of the well layer,

wherein said barrier layers individually comprise a barrier sublayer C which has been grown at a temperature higher than a growth temperature of said well layer, and barrier sublayers A, B and E which have been grown at a temperature lower than a growth temperature of said barrier sublayer C, said barrier sublayers A, B, C, and E are stacked, in this order, said barrier sublayer A is grown by maintaining a temperature lower than a growth temperature of said barrier sublayer C, said barrier sublayer B is grown during elevating a temperature from the growth temperature of said barrier sublayer A to the growth temperature of said barrier sublayer C, the difference between the growth temperature of said barrier sublayer C and the growth temperature of said barrier sublayer E is 50°

C. or more, said barrier sublayer E is grown by maintaining the lowered growth temperature after lowering the temperature.

3. A nitride semiconductor product according to claim 1 or 2, wherein the nitride semiconductor is represented by formula

In_xAl_yGa_1-x-yN(0≦

x<

1, 0≦

y<

1,0≦

x +y<

1).

4. A nitride semiconductor product according to claim 1 or 2, wherein the difference between the growth temperature of said barrier sublayer C and the growth temperature of said well layer is 50°

C. or more.

5. A nitride semiconductor product according to claim 1 wherein the difference between the growth temperature of said barrier sublayer C and the growth temperature of said barrier sublayer A is 50°

C. or more.

6. A nitride semiconductor product according to claim 1 or 2, wherein the growth temperature of said well layer falls within a range of 600°

C. to 1,000°

C.

7. A nitride semiconductor product according to claim 3, wherein said well layer comprises GaInN.

8. A nitride semiconductor product according to claim 3, wherein said barrier layer comprises GamiN or GaN.

9. A nitride semiconductor product according to claim 1 or 2, wherein at least one layer selected from said well layer and said barrier layer contains an n- type dopant.

10. A nitride semiconductor product according to claim 9, wherein said n-type dopant is Si.

11. A nitride semiconductor product according to claim 9, wherein said n-type dopant is Ge.

12. A nitride semiconductor product according to claim 9, wherein a concentration of said n-type dopant in the layer containing said n-type dopant varies periodically.

13. A nitride semiconductor product according to claim 12, wherein a layer with a higher concentration of said n-type dopant is not thicker than a layer with a lower concentration of said n-type dopant, in the layer containing said n-type dopant.

14. A nitride semiconductor product according to claim 9, wherein the layer containing said n-type dopant has an n-type dopant concentration of 1×

10¹⁶ to 5×

10¹⁹ cm<sup>−

3</sup>.

15. A nitride semiconductor light-emitting device comprising a nitride semiconductor product according to claim 1 or 2, a negative electrode provided on an n-type layer of said nitride semiconductor product and a positive electrode provided on a p-type layer of said nitride semiconductor product.

16. A light-emitting diode comprising a nitride semiconductor product according to claim 1 or 2.

17. A laser device comprising a nitride semiconductor product according to claim 1 or 2.

18. A lamp comprising a nitride semiconductor product according to claim 1 or 2.

2. A nitride semiconductor product comprising an n-type layer, a light-emitting layer, and a p-type layer which are formed of a nitride semiconductor and sequentially stacked on a substrate in the above order,

said light-emitting layer having a quantum well structure in which a well layer is sandwiched by barrier layers having band gaps wider than the band gap of the well layer,

wherein said barrier layers individually comprise a barrier sublayer C which has been grown at a temperature higher than a growth temperature of said well layer, and barrier sublayers D and E which have been grown at a temperature lower than a growth temperature of said barrier sublayer C, said barrier sublayers C, D and E are stacked, in this order, the difference between the growth temperature of said barrier sublayer C and the growth temperature of said barrier sublayer E is 50°

C. or more, said barrier sublayer D is grown during lowering the temperature from the growth temperature of said barrier sublayer C to the growth temperature of said barrier sublayer E, and said barrier sublayer E is grown by maintaining the lowered growth temperature after lowering the temperature.

19. A method for producing a nitride semiconductor product, said method comprising sequentially stacking on a substrate a nitride semiconductor n-type layer, a nitride semiconductor light-emitting layer of a quantum well structure, and a nitride semiconductor p-type layer, thereby producing a nitride semiconductor product having a quantum well structure, wherein said method comprises

growing a well layer;

subsequently, elevating a growth temperature;

growing a barrier layer of the quantum well structure at the elevated temperature, which is higher than a growth temperature of the well layer by 50°

C. or more;

subsequently, lowering the growth temperature again by 50°

C. or more; and

further growing the barrier layer at the lowered temperature.

20. A method for producing a nitride semiconductor product according to claim 19, which further comprises growing said barrier layer before elevating the growth temperature.

21. A method for producing a nitride semiconductor product according to claim 19, wherein growing of said barrier layer is performed in at least one step of elevating the growth temperature and lowering the growth temperature.

22. A method for producing a nitride semiconductor product according to claim 19, wherein said barrier layer contains an n-type dopant.

23. A method for producing a nitride semiconductor light-emitting device, said method comprising

a step of producing a nitride semiconductor product comprising an n-type layer, a light-emitting layer and a p-type layer by the method for producing a nitride semiconductor product according to claim 19, a step of removing a portion of a light-emitting layer and a p-type layer of the nitride semiconductor product , thereby exposing an n-type layer,

a step of providing a negative electrode on the exposed n-type layer, and

a step of providing a positive electrode on the p-type layer.

24. A method for producing a light-emitting diode, comprising a step of providing a lead to a nitride semiconductor light-emitting device produced by the method according to claim 23.

25. A method for producing a laser device, comprising a step of providing a lead to a nitride semiconductor light-emitting device produced by the method according to claim 23.

26. A method for producing a lamp, comprising a step of providing a cover containing a phosphor to a nitride semiconductor light-emitting device produced by the method according to claim 23.