Nitride semiconductor growth method, nitride semiconductor substrate, and nitride semiconductor device

• US 20070057276A1
• Filed: 11/14/2006
• Published: 03/15/2007
• Est. Priority Date: 04/11/1997
• Status: Active Grant

• Current Assignee: Nichia Chemical Industries Limited
• Original Assignee: Nichia Chemical Industries Limited
• Inventors: Nakamura, Shuji, Kozaki, Tokuya, Chocho, Kazuyuki, Kiyoku, Hiroyuki, Iwasa, Naruhito
• Granted Patent: US 7,442,254 B2
• Time in Patent Office: Days
• US Class Current: 257/103
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: C23C 16/042 using masks
• CPC Class Codes: C23C 16/303 Nitrides
• CPC Class Codes: C30B 25/02 Epitaxial-layer growth
• CPC Class Codes: C30B 29/40 AIIIBV compounds wherein A is B, Al, Ga, In or Tl and B is N, P, As, Sb or Bi
• CPC Class Codes: C30B 29/403 AIII-nitrides
• CPC Class Codes: C30B 29/406 Gallium nitride
• CPC Class Codes: H01L 21/0237 Materials
• CPC Class Codes: H01L 21/0242 Crystalline insulating materials
• CPC Class Codes: H01L 21/02433 Crystal orientation
• CPC Class Codes: H01L 21/02458 Nitrides
• CPC Class Codes: H01L 21/02502 consisting of two layers
• CPC Class Codes: H01L 21/0254 Nitrides
• CPC Class Codes: H01L 21/02576 N-type
• CPC Class Codes: H01L 21/0262 Reduction or decomposition of gaseous compounds, e.g. CVD
• CPC Class Codes: H01L 21/02639 Preparation of substrate for selective deposition
• CPC Class Codes: H01L 21/02642 Mask materials other than SiO2 or SiN
• CPC Class Codes: H01L 21/02647 Lateral overgrowth
• CPC Class Codes: H01L 33/007 comprising nitride compounds
• CPC Class Codes: H01L 33/16 with a particular crystal structure or orientation, e.g. polycrystalline, amorphous or porous
• CPC Class Codes: H01S 2301/173 : The laser chip comprising special buffer layers, e.g. dislocation prevention or reduction
• CPC Class Codes: H01S 2304/12 : Pendeo epitaxial lateral overgrowth [ELOG], e.g. for growing GaN based blue laser diodes
• CPC Class Codes: H01S 5/0213 : Sapphire, quartz or diamond based substrates
• CPC Class Codes: H01S 5/0422 : with n- and p-contacts on the same side of the active layer
• CPC Class Codes: H01S 5/2201 : in a specific crystallographic orientation
• CPC Class Codes: H01S 5/32025 : non-polar orientation
• CPC Class Codes: H01S 5/3211 : characterised by special cladding layers, e.g. details on band-discontinuities
• 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

A method of growing a nitride semiconductor crystal which has very few crystal defects and can be used as a substrate is disclosed. This invention includes the step of forming a first selective growth mask on a support member including a dissimilar substrate having a major surface and made of a material different from a nitride semiconductor, the first selective growth mask having a plurality of first windows for selectively exposing the upper surface of the support member, and the step of growing nitride semiconductor portions from the upper surface, of the support member, which is exposed from the windows, by using a gaseous Group 3 element source and a gaseous nitrogen source, until the nitride semiconductor portions grown in the adjacent windows combine with each other on the upper surface of the selective growth mask.

Claims

1. A nitride semiconductor device comprising:

a nitride semiconductor substrate having a first surface and second surface;

a nitride semiconductor structure having an indium-containing active layer, the nitride semiconductor structure having been grown on the first surface of the nitride semiconductor substrate; and

an n-side electrode formed on the second surface of the nitride semiconductor substrate, and

wherein the nitride semiconductor structure is at least partially formed in a ridge at its top surface, and

wherein the side surfaces of the nitride semiconductor structure is formed on or parallel to an M plane of the nitride semiconductor substrate.

2. The nitride semiconductor device according to claim 1, wherein the M plane of the nitride semiconductor substrate is formed by a cleaved surface.

3. The nitride semiconductor device according to claim 1, wherein the lower surface of the nitride semiconductor substrate is removed by removing a support member made up of a dissimilar substrate made of different material from the nitride semiconductor.

4. The nitride semiconductor device according to claim 3, wherein the removed surface of the nitride semiconductor substrate is polished by polishing the lower surface of the support member to expose the lower surface of the nitride semiconductor.

5. The nitride semiconductor device according to claim 1, wherein the nitride semiconductor substrate is made of GaN crystal, and the lower surface of the nitride semiconductor substrate is polished so as to expose the lower surface of the GaN crystal.

6. The nitride semiconductor device according to claim 1, wherein the nitride semiconductor substrate is formed on a support member made up of a dissimilar substrate made of different material from the nitride semiconductor, the support member being removed from the nitride semiconductor substrate.

7. A nitride semiconductor device according to claim 1, further comprising a buffer layer in contact with the nitride semiconductor substrate, the buffer layer being a distorted superlattice structure formed by alternately stacking first and second nitride semiconductor layers having different compositions.

8. A nitride semiconductor device according to claim 7, wherein the buffer layer is operable as an n-side cladding layer serving as a carrier confining layer.

9. A nitride semiconductor device according to claim 8, wherein the n-side cladding layer informed by alternately stacking an aluminum-containing nitride semiconductor doped with an n-type impurity and undoped GaN layers.

10. A nitride semiconductor device according to claim 1, wherein the nitride semiconductor substrate is doped with an n-type impurity.

11. A nitride semiconductor device according to claim 10, wherein the n-type impurity is one element selected from the group consisting of Si, Ge, Sn, and S.

12. A nitride semiconductor device according to claim 1, wherein the n-side electrode is made of a metal selected from the group consisting of Al, Ti, W, Cu, Zn, Sn, In, a multilayer thereof, and an alloy of thereof.

13. A nitride semiconductor device according to claim 1, wherein the n-side electrode is formed on substantially the entire second surface of the nitride semiconductor substrate.

14. A nitride semiconductor device according to claim 1, wherein the nitride semiconductor device is a light-emitting diode or laser diode device having the n-side electrode provided on the back surface of the nitride semiconductor substrate.

15. A nitride semiconductor device according to claim 1, wherein a n-side electrode having a two-layer structure made of Ti/Al is formed on the nitride semiconductor substrate.

16. A nitride semiconductor device according to claim 1, wherein the number of crystal defects in nitride semiconductor substrate is less than 1×

10⁸/cm².

17. A nitride semiconductor device according to claim 1, wherein the nitride semiconductor substrate is doped with an n-type impurity such that the n-type impurity concentration has a gradient, wherein the gradient from said first surface to said second surface is from lesser concentration to greater concentration.

18. A nitride semiconductor device according to claim 17, wherein the concentration gradient is continuous or stepwise.

19. A nitride semiconductor device according to claim 18, wherein the n-type impurity is one element selected from the group consisting of Si, Ge, Sn, and S.