SEMICONDUCTOR MODIFICATION PROCESS FOR CONDUCTIVE AND MODIFIED ELECTRICAL REGIONS AND RELATED STRUCTURES

• US 20190221710A1
• Filed: 01/07/2019
• Published: 07/18/2019
• Est. Priority Date: 02/13/2014
• Status: Active Grant

• Current Assignee: META Platforms Technologies LLC (Meta Platforms, Inc. (f/k/a Facebook, Inc.))
• Original Assignee: Facebook Technologies, LLC (Meta Platforms, Inc. (f/k/a Facebook, Inc.))
• Inventors: Bonar, James Ronald, Valentine, Gareth John, Gorton, Stephen Warren, Gong, Zheng, Small, James
• Granted Patent: US 10,644,197 B2
• Time in Patent Office: Days
• CPC Class Codes: H01L 33/0075 comprising nitride compounds
• CPC Class Codes: H01L 33/0095 Post-treatment of devices, e.g. annealing, recrystallisation or short-circuit elimination
• CPC Class Codes: H01L 33/145 with a current-blocking structure
• CPC Class Codes: H01S 3/005 Optical devices external to the laser cavity, specially adapted for lasers, e.g. for homogenisation of the beam or for manipulating laser pulses, e.g. pulse shaping shaping laser beam for working metal or other materials B23K26/06; optical elements, systems or apparatus in general G02B
• CPC Class Codes: H01S 5/00 Semiconductor lasers superluminescent diodes H01L33/00
• CPC Class Codes: H01S 5/021 Silicon based substrates
• CPC Class Codes: H01S 5/04253 having specific optical properties, e.g. transparent electrodes
• CPC Class Codes: H01S 5/04257 having positive and negative electrodes on the same side of the substrate
• CPC Class Codes: H01S 5/18308 having a special structure for lateral current or light confinement
• CPC Class Codes: H01S 5/18341 Intra-cavity contacts
• CPC Class Codes: H01S 5/2068 obtained by radiation treatment or annealing
• CPC Class Codes: H01S 5/2086 lateral etch control, e.g. mask induced
• CPC Class Codes: H01S 5/34333 with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser

Abstract

There is herein described a process for providing improved device performance and fabrication techniques for semiconductors. More particularly, the present invention relates to a process for forming features, such as pixels, on GaN semiconductors using a p-GaN modification and annealing process. The process also relates to a plasma and thermal anneal process which results in a p-GaN modified layer where the annealing simultaneously enables the formation of conductive p-GaN and modified p-GaN regions that behave in an n-like manner and block vertical current flow. The process also extends to Resonant-Cavity Light Emitting Diodes (RCLEDs), pixels with a variety of sizes and electrically insulating planar layer for electrical tracks and bond pads.

Claims

1. A method for fabricating an electronic component, comprising:

exposing a portion of a p-type GaN layer of the electrical component to a plasma treatment to convert the portion of the p-type GaN layer to n-type GaN, another portion of the p-type GaN layer being shielded from the plasma treatment; and

subsequent to the plasma treatment, annealing the p-type GaN layer to form a region that blocks current flow from the n-type GaN and a conductive contact from the other portion of the p-type GaN layer shielded from the plasma treatment.

2. The method of claim 1, further comprising:

depositing a spreading layer on the p-type GaN layer;

depositing a mask feature onto the spreading layer over the other portion of the p-type GaN layer, the mask feature exposing a portion of the spreading layer over the portion of the p-type GaN layer; and

prior to exposing the portion of the p-type GaN layer to the plasma treatment, removing the portion of the spreading layer over the portion of the p-type GaN layer.

3. The method of claim 2, further comprising, prior to annealing the p-type GaN layer, removing the mask feature from the spreading layer.

4. The method of claim 1, further comprising:

depositing a mask feature onto the other portion of the p-type GaN layer, the other portion of the p-type GaN layer being shielded from the plasma treatment by the mask feature; and

prior to annealing the p-type GaN layer, removing the mask feature from the other portion of the p-type GaN layer.

5. The method of claim 4, further comprising, subsequent to exposing the portion of the p-type GaN layer to the plasma treatment and prior to annealing the p-type GaN layer, depositing a spreading layer on the portion of the p-type GaN layer.

6. The method of claim 1, further comprising:

depositing a spreading layer on the p-type GaN layer; and

depositing a mask feature onto the spreading layer over the other portion of the p-type GaN layer, the mask feature exposing a portion of the spreading layer over the portion of the p-type GaN layer, and wherein;

exposing the portion of the p-type GaN layer to the plasma treatment includes exposing the portion of the spreading layer over the portion of the p-type GaN layer to the plasma treatment.

7. The method of claim 6, further comprising, prior to annealing the p-type GaN layer, removing the mask feature from the spreading layer.

8. The method of claim 6, wherein the spreading layer is less than or equal to 5 um in thickness.

9. The method of claim 6, wherein the spreading layer includes at least one of:

Ni/Au;

Ni/Pt;

Au/Pt;

Pt/Ni/Au;

Ni/Ag;

Pd;

or

Ni/ITO.

10. The method of claim 6, wherein the region that blocks current flow permits no or little lateral current conduction across the portion of the spreading layer.

11. The method of claim 1, wherein the region that blocks current flow are non-conductive to vertical currents.

12. The method of claim 1, wherein exposing the portion of the p-type GaN layer to the plasma treatment includes exposing the portion of the p-type GaN layer to a plasma for 3000 seconds with a plasma power of 200 Watts and a gas flow of 20 sccm.

13. The method of claim 1, wherein annealing the p-type GaN layer includes one of:

exposing the p-type GaN layer to a temperature of 500°

C.;

or

rapid thermal annealing the p-type GaN layer for 120 seconds to a temperature of 500°

C.

14. The method of claim 1, wherein exposing the portion of the p-type GaN layer to the plasma treatment includes exposing the portion of the p-type GaN layer to a plasma including at least one of:

CH₃;

Ar;

CHF₃/Ar;

C₂F₆;

CF₄;

or

H₂.

15. The method of claim 1, further comprising forming a mirror over the conductive contact and at least a portion of the region that blocks current flow.

16. The method of claim 1, further comprising forming a mesa in the p-type GaN layer, the region that blocks current flow and the conductive contact being at a top side of the mesa opposite a base of the mesa.

17. The method of claim 16, wherein the mesa includes a straight, sloped, or parabolic sidewall defined between the top side and the base of the mesa.

18. The method of claim 16, wherein the base of the mesa is larger than an area of the conductive contact.

19. The method of claim 1, further comprising forming a p-contact and an n-contact that are electrically isolated from each other by the region that blocks current flow.

20. The method of claim 1, wherein the electrical component includes one of:

a micro light emitting diode (LED);

a resonant-cavity LED;

or

a vertical cavity surface emitting layer (VCSEL).