Group III-nitride layers with patterned surfaces

• US 7,084,563 B2
• Filed: 07/13/2005
• Issued: 08/01/2006
• Est. Priority Date: 03/26/2003
• Status: Expired due to Term

• Current Assignee: Alcatel-Lucent USA, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Chowdhury, Aref, Ng, Hock Min, Slusher, Richart Elliott
• Primary Examiner(s): WILLIAMS, JOSEPH L
• Application Number:
  US11/180,350
• Publication Number:
  US 20050269593A1
• Time in Patent Office: 384 Days
• Field of Search: 313498-501, 313/309, 313/336, 313/351, 313/355, 257/98, 257/99, 257/10, 438/94, 438/172, 438/602, 438/606, 438/604, 445 23- 25, 445/49, 445/50, 445/51
• US Class Current: 313/498
• CPC Class Codes: B81B 1/00 Devices without movable or flexible elements, e.g. microcapillary devices
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G02B 2006/12035 Materials
• CPC Class Codes: G02B 6/1225 comprising photonic band-gap structures or photonic lattices
• CPC Class Codes: H01J 1/304 Field-emissive cathodes
• CPC Class Codes: H01J 3/022 with microengineered cathode, e.g. Spindt-type
• CPC Class Codes: H01J 9/025 of field emission cathodes
• CPC Class Codes: H01L 21/0254 Nitrides
• CPC Class Codes: H01L 21/02639 Preparation of substrate for selective deposition
• CPC Class Codes: H01L 21/30612 Etching of AIIIBV compounds

Abstract

An apparatus includes a crystalline substrate, a layer of a first group III-nitride located on a planar surface of the substrate, and a layer of a second group III-nitride located over the layer of the first group III-nitride. The first and second group III-nitrides have different alloy compositions. The layer of second group III-nitride may have a pattern of columnar holes or trenches therein. The apparatus may include a plurality of pyramidal field-emitters that include the second group III-nitride.

Claims

1. An apparatus, comprising:

a crystalline substrate with a planar surface; and

a plurality of pyramidal field-emitters located over a portion the surface;

a layer of a first group III-nitride located on another portion of the surface, the field-emitters comprising a second group III-nitride;

a layer of the second group-III nitride semiconductor being over the layer of a first group III-nitride and being free of pyramidal surface structures; and

wherein the first and second group III-nitrides have different alloy compositions.

2. The apparatus of claim 1, wherein the first group III-nitride comprises aluminum and the second group III-nitride comprises gallium.

3. The apparatus of claim 1, further comprising:

a phosphor screen located to receive electrons emitted by the pyramidal field-emitters; and

a plurality of gate electrodes located between the layer of the second group III-nitride and the phosphor screen.

4. The apparatus of claim 3, wherein the gate electrodes are mechanically supported by the layer of the second group III-nitride.

5. An apparatus, comprising:

a crystalline substrate having a planar surface;

a mechanically patterned layer of a first group III-nitride being located on the planar surface; and

a layer of a second group III-nitride being located on the mechanically patterned layer of a first group III-nitride, the layer of a second group III-nitride having a thickness of about 2 μ

m or more and having a pattern of columnar holes or trenches therein; and

wherein the holes or trenches form a regular array; and

wherein the first and second group III-nitrides have different alloy compositions.

6. The apparatus of claim 5, wherein bottom surfaces of at least some of the holes or trenches contact the planar surface.

7. The apparatus of claim 6, wherein the layer of a second group III-nitride comprises a regular two-dimensional array of pillars.

8. The apparatus of claim 5, wherein the second group III-nitride comprises gallium and the first group III-nitride comprises aluminum.