Gallium nitride semiconductor structures including a lateral gallium nitride layer that extends from an underlying gallium nitride layer

• US 6,051,849 A
• Filed: 02/27/1998
• Issued: 04/18/2000
• Est. Priority Date: 02/27/1998
• Status: Expired due to Term

• Current Assignee: North Carolina State University (University of North Carolina System)
• Original Assignee: North Carolina State University (University of North Carolina System)
• Inventors: Davis, Robert F., Zheleva, Tsvetanka, Bremser, Michael D., Nam, Ok-Hyun
• Primary Examiner(s): COLEMAN, WILLIAM D
• Application Number:
  US09/032,190
• Time in Patent Office: 781 Days
• Field of Search: 257/76, 257/94, 257/96, 257/103
• US Class Current: 257/103
• CPC Class Codes: H01L 21/0237 Materials
• CPC Class Codes: H01L 21/02378 Silicon carbide
• 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 21/0262 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
• CPC Class Codes: H01L 33/007 comprising nitride compounds

Abstract

A gallium nitride semiconductor layer is fabricated by masking an underlying gallium nitride layer with a mask that includes an array of openings therein, and growing the underlying gallium nitride layer through the array of openings and onto the mask, to thereby form an overgrown gallium nitride semiconductor layer. Although dislocation defects may propagate vertically from the underlying gallium nitride layer to the grown gallium nitride layer through the mask openings, the overgrown gallium nitride layer is relatively defect free. The overgrown gallium nitride semiconductor layer may be overgrown until the overgrown gallium nitride layer coalesces on the mask, to form a continuous overgrown monocrystalline gallium nitride semiconductor layer. The gallium nitride semiconductor layer may be grown using metalorganic vapor phase epitaxy. Microelectronic devices may be formed in the overgrown gallium nitride semiconductor layer.

Claims

1. A gallium nitride semiconductor structure comprising:

an underlying gallium nitride layer having defect density of at least 10⁸ cm^-2 ;

a patterned layer that includes an array of openings therein, on the underlying gallium nitride layer;

a vertical gallium nitride layer having defect density of at least 10⁸ cm^-2 that extends from the underlying gallium nitride layer and through the array of openings; and

a lateral gallium nitride layer having defect density of less than 10⁴ cm^-2 that extends from the vertical gallium nitride layer onto the patterned layer opposite the underlying gallium nitride layer.

2. A structure according to claim 1 further comprising:

a plurality of microelectronic devices in the lateral gallium nitride layer.

3. A structure according to claim 1 wherein the lateral gallium nitride layer is a continuous monocrystalline gallium nitride semiconductor layer.

4. A structure according to claim 1 further comprising a substrate, and wherein the underlying gallium nitride layer is on the substrate.

5. A structure according to claim 4 further comprising a buffer layer between the substrate and the underlying gallium nitride layer.

6. A structure according to claim 1 wherein the patterned layer includes an array of openings therein, the openings extending along a <

1100>

direction of the underlying gallium nitride layer.

7. A structure according to claim 1 wherein the patterned layer includes an array of openings therein, the openings extending along a <

1120>

direction of the underlying gallium nitride layer.

8. A structure according to claim 1 wherein the patterned layer includes an array of first openings therein that extend along a <

1120>

direction of the underlying gallium nitride layer, and an array of second openings therein that extend along a <

1100>

direction of the underlying gallium nitride layer.

9. A structure according to claim 8 wherein the array of first openings and the array of second openings are arranged in a rectangle on the underlying gallium nitride layer, the rectangle having edges of predetermined lengths, and wherein a ratio of the of the predetermined lengths is proportional to a ratio of growth rates of a {1120} facet and a {1101} facet of the underlying gallium nitride layer.

10. A structure according to claim 1 further comprising:

a microelectronic device in the lateral gallium nitride layer.

13. A layer according to claim 1 wherein the spaced apart regions are stripes that extend along a <

1120>

direction of the layer.

11. A monocrystalline gallium nitride layer of a predetermined defect density, including a plurality of spaced apart regions of lower defect density than the predetermined defect density, wherein the predetermined defect density is at least 10⁸ cm^-2 and wherein the lower defect density is less than 10⁴ cm^-2.

12. A layer according to claim 11 wherein the spaced apart regions are stripes that extend along a <

1100>

direction of the layer.

14. A layer according to claim 11 wherein the spaced apart regions comprise an array of first spaced apart regions that extend along a <

1120>

direction of the layer, and an array of second spaced apart regions that extend along a <

1100>

direction of the layer.

15. A layer according to claim 14 wherein the array of first regions and the array of second regions are arranged in a rectangle in the layer, the rectangle having edges of predetermined lengths, and wherein a ratio of the of the predetermined lengths is proportional to a ratio of growth rates of a {1120} facet and a {1101} facet of the layer.

16. A layer according to claim 11 further comprising:

at least one microelectronic device in at least one of the spaced apart regions.

17. A gallium nitride semiconductor structure comprising:

an underlying gallium nitride layer, having defect density of at least 10⁸ cm^-2 ;

a lateral gallium nitride layer having defect density of less than 10⁴ cm^-2 that extends from the underlying gallium nitride layer; and

at least one microelectronic device in the lateral gallium nitride layer.

18. A structure according to claim 17 further comprising:

a vertical gallium nitride layer between the underlying gallium nitride layer and the lateral gallium nitride layer.

19. A structure according to claim 17 wherein the lateral gallium nitride layer is a continuous monocrystalline gallium nitride semiconductor layer.

20. A structure according to claim 17 further comprising a substrate, and wherein the underlying gallium nitride layer is on the substrate.

21. A structure according to claim 20 further comprising a buffer layer between the substrate and the underlying gallium nitride layer.

22. A structure according to claim 17 wherein the lateral gallium nitride layer includes spaced apart stripes that extend along a <

1100>

direction of the underlying gallium nitride layer.

23. A structure according to claim 17 wherein the lateral gallium nitride layer includes spaced apart stripes that extend along a <

1120>

direction of the underlying gallium nitride layer.

24. A structure according to claim 17 wherein the lateral gallium nitride layer includes an array of first spaced apart regions that extend along a <

1120>

direction of the underlying gallium nitride layer, and an array of second spaced apart regions that extend along a <

1100>

direction of the underlying gallium nitride layer.

25. A structure according to claim 24 wherein the array of first regions and the array of second regions are arranged in a rectangle in the lateral gallium nitride layer, the rectangle having edges of predetermined lengths, and wherein a ratio of the of the predetermined lengths is proportional to a ratio of growth rates of a {1120} facet and a {1101} facet of the lateral gallium nitride layer.