Method for making a light emitting diode having three dimensional nano-structures

• US 9,070,823 B2
• Filed: 12/27/2012
• Issued: 06/30/2015
• Est. Priority Date: 03/30/2012
• Status: Active Grant

• Current Assignee: Hon Hai Precision Industry Co., Ltd., Tsinghua University
• Original Assignee: Hon Hai Precision Industry Co., Ltd., Tsinghua University
• Inventors: Jin, Yuan-Hao, Li, Qun-Qing, Fan, Shou-Shan
• Primary Examiner(s): Nikmanesh, Seahvosh
• Assistant Examiner(s): PATERSON, BRIGITTE A
• Application Number:
  US13/728,043
• Publication Number:
  US 20130260492A1
• Time in Patent Office: 915 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: H01L 2933/0016 relating to electrodes
• CPC Class Codes: H01L 2933/0083 Periodic patterns for optical field-shaping in or on the semiconductor body or semiconductor body package, e.g. photonic bandgap structures
• CPC Class Codes: H01L 33/0075 comprising nitride compounds
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/0095 Post-treatment of devices, e.g. annealing, recrystallisation or short-circuit elimination
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/24 of the light emitting region, e.g. non-planar junction
• CPC Class Codes: H01L 33/405 Reflective materials

Abstract

A method for making a LED comprises following steps. A substrate having a surface is provided. A first semiconductor layer, an active layer and a second semiconductor pre-layer is formed on the surface of the substrate. A patterned mask layer is applied on a surface of the second semiconductor pre-layer. A number of three-dimensional nano-structures is formed on the second semiconductor pre-layer and the patterned mask layer is removed. The substrate is removed and a first electrode is formed on a surface of the first semiconductor layer away from the active layer. A second electrode is formed to electrically connect with the second semiconductor pre-layer.

Claims

1. A method for making a light emitting diode, comprising steps of:

providing a substrate having a first surface;

forming a first semiconductor layer, an active layer and a second semiconductor pre-layer on the first surface;

applying a patterned mask layer on a second semiconductor pre-layer surface, wherein the patterned mask layer comprises a plurality of linear walls aligned side by side, and a groove is defined between each adjacent linear walls to form an exposed portion of the second semiconductor pre-layer surface;

etching the exposed portion of the second semiconductor pre-layer surface along a first direction to form two sidewalls in the second semiconductor pre-laver covered by the plurality of linear walls, and etching the two sidewalls along a second direction, and removing the patterned mask layer to form a plurality of three-dimensional nano-structures, wherein the first direction is perpendicular to the second semiconductor pre-layer surface, the second direction is paralleled to the second semiconductor pre-layer surface, and a cross-section of each three-dimensional nano-structure is a convex arc shape;

removing the substrate to form an exposed first semiconductor layer surface located away from the active layer;

covering the exposed first semiconductor layer surface by a first electrode; and

electrically connecting a second electrode with the second semiconductor pre-layer.

2. The method of claim 1, wherein a width of the groove ranges from about 100 nm to about 200 nm.

3. The method of claim 1, wherein a distance between adjacent grooves ranges from about 300 nm to about 400 nm.

4. The method of claim 1, wherein the exposed portion is etched by a reactive atmosphere comprising chlorine gas and argon gas.

5. The method of claim 3, wherein a chlorine input flow rate is lower than an argon input flow rate.

6. The method of claim 5, wherein the chlorine input flow rate is in a range from about 4 standard-state cubic centimeters per minute to about 20 standard-state cubic centimeters per minute, and the argon input flow rate is in a range from about 10 standard-state cubic centimeters per minute to about 60 standard-state cubic centimeters per minute.

7. The method of claim 1, further comprising a step of forming a reflector layer to cover the first electrode.

8. The method of claim 1, wherein removing the substrate by laser irradiation, etching, or thermal expansion and contraction.

9. The method of claim 1, wherein the cross-section of each three-dimensional nano-structure is a semicircle having a diameter of about 320 nm.

10. The method of claim 4, wherein a working pressure of the reactive atmosphere is a range from about 2 Pa to about 10 Pa, and an etching time of the reactive atmosphere is in a range from about 1 minute to about 2.5 minutes.