N-type gallium-nitride layer having multiple conductive intervening layers

• US 9,012,939 B2
• Filed: 08/02/2011
• Issued: 04/21/2015
• Est. Priority Date: 08/02/2011
• Status: Active Grant

• Current Assignee: Seoul Semiconductor Co., Ltd.
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Chen, Zhen, Fu, Yi
• Primary Examiner(s): Such, Matthew W
• Assistant Examiner(s): Naraghi, Ali
• Application Number:
  US13/196,828
• Publication Number:
  US 20130032836A1
• Time in Patent Office: 1,358 Days
• Field of Search: 257 98-100
• US Class Current: 257/98
• CPC Class Codes: H01L 2224/2929 with a principal constituent of the material being a polymer, e.g. polyester, phenolic based polymer, epoxy
• CPC Class Codes: H01L 2224/29339 Silver [Ag] as principal constituent
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01322 Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2924/0655 Polyacetal
• CPC Class Codes: H01L 2924/10253 Silicon [Si]
• CPC Class Codes: H01L 33/007 comprising nitride compounds
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/12 with a stress relaxation structure, e.g. buffer layer
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls

Abstract

A vertical GaN-based blue LED has an n-type layer comprising multiple conductive intervening layers. The n-type layer contains a plurality of periods. Each period of the n-type layer includes a gallium-nitride (GaN) sublayer and a thin conductive aluminum-gallium-nitride (AlGaN:Si) intervening sublayer. In one example, each GaN sublayer has a thickness substantially more than 100 nm and less than 1000 nm, and each AlGaN:Si intervening sublayer has a thickness less than 25 nm. The entire n-type layer is at least 2000 nm thick. The AlGaN:Si intervening layer provides compressive strain to the GaN sublayer thereby preventing cracking. After the epitaxial layers of the LED are formed, a conductive carrier is wafer bonded to the structure. The silicon substrate is then removed. Electrodes are added and the structure is singulated to form a finished LED device. Because the AlGaN:Si sublayers are conductive, the entire n-type layer can remain as part of the finished LED device.

Claims

1. A Light Emitting Diode (LED) device for emitting non-monochromatic light, the LED device comprising:

an n-type layer that comprises a plurality of periods including a plurality of gallium-nitride (GaN) sublayers and a plurality of aluminum-gallium-nitride doped with silicon (AlGaN;

Si) intervening sublayers, each of the AlGaN;

Si intervening sublayers sandwiched by the gallium-nitride (GaN) sublayers, the gallium-nitride (GaN) sublayers located at top and bottom of the period, respectively;

a p-type layer;

an active layer disposed between the n-type layer and the p-type layer, wherein the active layer includes an amount of indium;

a conductive carrier;

a first electrode; and

a second electrode adapted to conduct a current, wherein the current flows from the second electrode, through the p-type layer, through the active layer, through the n-type layer, and to the first electrode thereby causing the non-monochromatic light to be emitted.

2. The LED device of claim 1, wherein the n-type layer has a thickness of at least two thousand nanometers.

3. The LED device of claim 1, wherein each GaN sublayer has a thickness of less than one thousand nanometers, and wherein each AlGaN:

Si intervening sublayer has a thickness of less than twenty-five nanometers.

4. The LED device of claim 1, wherein the AlGaN:

Si intervening sublayers are conductive, and wherein the AlGaN;

Si intervening sublayers have a silicon concentration greater than 1×

10¹⁸ atoms/cm³.

5. The LED device of claim 1, wherein the n-type layer has a roughened surface.

6. The LED device of claim 1, further comprising:

a eutectic bond metal layer disposed between the conductive carrier and the p-type layer.

7. The LED device of claim 1, wherein each of the GaN sublayers has a thickness that is substantially greater than one hundred nanometers and is less than one thousand nanometers.

8. The LED device of claim 1, wherein the current flows from the second electrode, through the conductive carrier, through the p-type layer, through the active layer, through the n-type layer, and to the first electrode thereby causing the non-monochromatic light to be emitted.

9. A Light Emitting Diode (LED) device comprising:

an n-type layer comprising a plurality of periods, wherein each period of the n-type layer includes a gallium-nitride (GaN) sublayer and an aluminum-gallium-nitride doped with silicon (AlGaN;

Si) intervening sublayer, wherein each GaN sublayer has a thickness that is substantially greater than one hundred nanometers and is less than one thousand nanometers, wherein each AlGaN;

Si intervening sublayer has a thickness of less than twenty-five nanometers, wherein each AlGaN;

Si intervening sublayer has a silicon concentration greater than 1×

10¹⁸ atoms/cm³, and wherein the n-type layer has a thickness of at least two thousand nanometers;

a p-type layer; and

an active layer disposed between the n-type layer and the p-type layer, wherein current flow between the p-type layer and the n-type layer causes the LED device to emit light.

10. The LED device of claim 9, further comprising:

a carrier; and

a layer of bond metal disposed between the p-type layer and the carrier.

11. The LED device of claim 10, further comprising:

a first electrode; and

a second electrode, where the current flow flows from the second electrode in a current path through the carrier, through the bond metal, through the p-type layer, through the active layer, through the n-type layer, and to the first electrode.

12. A Light Emitting Diode (LED) device comprising:

an n-type layer comprising a plurality of periods, wherein each period of the n-type layer includes;

a gallium-nitride (GaN) sublayer, wherein each GaN sublayer has a thickness that is substantially greater than one hundred nanometers and is less than one thousand nanometers; and

a compressive strain layer that provides a compressive strain to the GaN sublayer and conducts current;

a p-type layer; and

an active layer disposed between the n-type layer and the p-type layer, wherein current flow between the p-type layer and the n-type layer passes through the compressive strain layer of each period of the n-type layer and causes the LED device to emit light.

13. The LED device of claim 12, wherein the current is conducted between the GaN sublayers.

14. The LED device of claim 13, wherein the compressive strain layer is a sublayer that has a thickness of less than twenty-five nanometers.

15. The LED device of claim 14, wherein the compressive strain layer is an aluminum-gallium-nitride doped with silicon (AlGaN:

Si) intervening sublayer that has a thickness of less than twenty-five nanometers.