Integrating active matrix inorganic light emitting diodes for display devices

• US 9,293,476 B2
• Filed: 10/20/2014
• Issued: 03/22/2016
• Est. Priority Date: 11/23/2011
• Status: Expired due to Fees

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: GlobalFoundries, Inc.
• Inventors: Bedell, Stephen W., Hekmatshoartabari, Bahman, Sadana, Devendra K., Shahidi, Ghavam G., Shahrjerdi, Davood
• Primary Examiner(s): AHMED, SELIM U
• Application Number:
  US14/518,023
• Publication Number:
  US 20150102359A1
• Time in Patent Office: 519 Days
• Field of Search: 257/59, 257/72, 257/76, 257/E33.025, 257/E33.071
• US Class Current: 1/1
• CPC Class Codes: H01L 27/1218 with a particular composition or structure of the substrate
• CPC Class Codes: H01L 27/156 two-dimensional arrays
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/42 Transparent materials

Abstract

A method of forming an active matrix, light emitting diode (LED) array includes removing, from a base substrate, a layer of inorganic LED material originally grown thereupon; and bonding the removed layer of inorganic LED material to an active matrix, thin film transistor (TFT) backplane array.

Claims

1. An active matrix, light emitting diode (LED) array, comprising:

a first subpixel unit having layer of a first inorganic LED material bonded to an active matrix, thin film transistor (TFT) backplane array; and

a second subpixel unit having a layer of a second inorganic LED material bonded to the active matrix, TFT backplane array;

the first inorganic LED material is different from the second inorganic LED material, the first subpixel unit having a different light emission characteristic than the second subpixel unit.

2. The array of claim 1, further comprising a plurality of color filters formed on at least one of a top and bottom surface of the active matrix TFT backplane array.

3. The array of claim 1, wherein the inorganic LED material comprises gallium nitride (GaN).

4. The array of claim 1, further comprising a bottom contact electrode disposed between the backplane array and the inorganic LED material.

5. The array of claim 4, wherein the bottom contact electrode is one or more of:

a transparent conductive oxide (TCO), a metal, and a TCO/metal bilayer.

6. The array of claim 5, further comprising a top contact electrode formed on a top surface of the inorganic LED material.

7. The array of claim 6, wherein the top contact electrode is one or more of:

a transparent conductive oxide (TCO), a metal, and a TCO/metal bilayer.

8. The array of claim 1, wherein the layer of inorganic LED material is attached to a flexible handle layer, the flexible handle layer being configured to facilitate a spalling process within the inorganic LED material that exfoliates the inorganic LED material from a base substrate by application of a mechanical force on the flexible handle layer.

9. The array of claim 8, wherein the flexible handle layer comprises a polyimide material.

10. The array of claim 8, further comprising one or more stress layers formed between the inorganic LED material and the flexible handle layer.

11. The array of claim 10, further comprising an adhesion layer that forms an interface between the inorganic LED material and the one or more stress layers.

12. The array of claim 11, wherein the one or more stress layers comprise metal.

13. The array of claim 12, wherein a thickness of the one or more stress layers is selected so as exfoliate the inorganic LED material from the base substrate at a desired location with respect to thickness of the exfoliated inorganic LED material.