DISLOCATION REDUCTION IN NON-POLAR III-NITRIDE THIN FILMS

• US 20080135853A1
• Filed: 09/10/2007
• Published: 06/12/2008
• Est. Priority Date: 04/15/2002
• Status: Active Grant

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Speck, James S., DenBaars, Steven P., Nakamura, Shuji, Craven, Michael D.
• Granted Patent: US 8,809,867 B2
• Time in Patent Office: Days
• US Class Current: 257/76
• CPC Class Codes: C30B 25/02 Epitaxial-layer growth
• CPC Class Codes: C30B 25/04 Pattern deposit, e.g. by using masks
• CPC Class Codes: C30B 25/105 by irradiation or electric discharge
• CPC Class Codes: C30B 25/18 characterised by the substrate
• CPC Class Codes: C30B 29/403 AIII-nitrides
• CPC Class Codes: C30B 29/406 Gallium nitride
• CPC Class Codes: C30B 29/605 Products containing multiple oriented crystallites, e.g. columnar crystallites
• 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 21/0254 Nitrides
• CPC Class Codes: H01L 21/02609 Crystal orientation
• 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 21/02647 Lateral overgrowth

Abstract

Lateral epitaxial overgrowth of non-polar III-nitride seed layers reduces threading dislocations in the non-polar III-nitride thin films. First, a thin patterned dielectric mask is applied to the seed layer. Second, a selective epitaxial regrowth is performed to achieve a lateral overgrowth based on the patterned mask. Upon regrowth, the non-polar III-nitride films initially grow vertically through openings in the dielectric mask before laterally overgrowing the mask in directions perpendicular to the vertical growth direction. Threading dislocations are reduced in the overgrown regions by (1) the mask blocking the propagation of dislocations vertically into the growing film and (2) the bending of dislocations through the transition from vertical to lateral growth.

Claims

1. An (Al, B, In, Ga)N-based device grown on non-polar III-nitride with a dislocation density of less than 2.6×

10¹⁰ cm<sup>−

2</sup>.

2. The (Al, B, In, Ga)N-based device of claim 1, wherein the III-nitride has a dislocation density of less than 1×

10⁸ cm<sup>−

2</sup>.

3. The (Al, B, In, Ga)N-based device of claim 2, wherein the III-nitride has a stacking fault density less than 3.8×

10⁵ cm<sup>−

1</sup>.

4. The (Al, B, In, Ga)N-based device of claim 1, wherein the device is grown using metalorganic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE).

5. The (Al, B, In, Ga)N-based device of claim 1, wherein the device is an InGaN-based light emitting diode or laser diode.

6. The (Al, B, In, Ga)N-based device of claim 1, wherein the device is an AlGaN or GaN high electron mobility transistor (HEMT) or heterojunction bipolar transistor (HBT).

7. A method of reducing threading dislocation densities in a non-polar III-nitride thin film, comprising:

(a) depositing a dielectric regrowth mask on the non-polar III-nitride thin film;

(b) patterning the deposited mask; and

(c) performing a selective regrowth to achieve an overgrowth based on the patterned mask.

8. The method of claim 7, wherein the non-polar III-nitride thin film comprises a seed layer.

9. The method of claim 7, wherein the deposited mask is patterned with long, narrow stripe openings oriented in a variety of crystallographic directions.

10. The method of claim 7, wherein the overgrowth comprises laterally overgrown III-nitride formed stripes.

11. The method of claim 7, wherein the performing step comprises performing a selective regrowth of the III-nitride to achieve the overgrowth based on the patterned mask, and the III-nitride initially grows vertically through openings in the mask before laterally overgrowing the mask in directions perpendicular to a vertical growth direction.

12. The method of claim 11, wherein laterally overgrown regions contain reduced dislocation densities, as compared to regions that grow vertically through openings in the mask.

13. The method of claim 12, wherein dislocations are reduced in the overgrown regions by the mask blocking propagation of dislocations vertically into the growing film.

14. The method of claim 12, wherein dislocations are reduced in the overgrown regions by bending of dislocations through a transition from vertical to lateral growth.

15. A device manufactured using the method of claim 7.