Full-color light-emitting diode micro-display and the fabrication method thereof
A full-color LED micro-display having a plurality of pixels is disclosed. Each pixel includes a first LED comprising a blue/green dual wavelength LED structure for emitting blue light; a second LED comprising the blue/green dual wavelength LED structure for emitting green light; and a third LED comprising a monochrome red LED structure for emitting red light. The blue/green dual wavelength LED structure includes a dual wavelength MQWs active region of a first material with two emission peaks. The dual wavelength MQWs active region includes a first quantum well stack, a second quantum well stack, and a third quantum well stack. The first and the third quantum well stack are configured for generating the blue light, and the second quantum well stack is configured for generating the green light. The monochrome red LED structure further comprises a red emitting MQWs active region of a second material with a second emission peak.
1. A full-color light-emitting diode (LED) micro-display comprising a plurality of pixels, each pixel comprising:
a first LED comprising a blue/green dual wavelength LED structure for emitting blue light;
a second LED comprising the blue/green dual wavelength LED structure for emitting green light; and
a third LED comprising a monochrome red LED structure for emitting red light, wherein:
the blue/green dual wavelength LED structure further comprises a dual wavelength multiple quantum wells (MQWs) active region of a first material with two emission peaks, wherein the dual wavelength MQWs active region comprises a first quantum well stack, a second quantum well stack, and a third quantum well stack;
the first quantum well stack and the third quantum well stack are configured for generating the blue light, and the second quantum well stack is configured for generating the green light; and
the monochrome red LED structure further comprises a red emitting MQWs active region of a second material with a second emission peak.
2. The full-color LED micro-display of claim 1 , wherein the first material is Indium gallium nitride (InGaN) and the second material is Aluminum gallium indium phosphide (AlGaInP).
3. The full-color LED micro-display of claim 2 , wherein the first quantum well stack and the third quantum well stack each comprises one or more blue emitting quantum wells (QWs) and one or more quantum barrier layers; and the second quantum well stack comprises one or more green emitting QWs and one or more quantum barrier layers.
4. The full-color LED micro-display of claim 3 , wherein the first quantum well stack comprises three blue emitting QWs; the second quantum well stack comprises one green emitting QW; and the third quantum well stack comprises one blue emitting QW.
5. The full-color LED micro-display of claim 4 , wherein:
each blue emitting QW is an In x Ga 1−x N layer with a first thickness between 1 and 10 nm, wherein x is any value between 0.1 and 0.2; and
the green emitting QW is an In x Ga 1−x N layer with a second thickness between 1 and 5 nm, wherein y is any value between 0.2 and 0.3.
6. The full-color LED micro-display of claim 2 , wherein the blue/green dual wavelength LED structure further comprising:
a buffer layer comprising an undoped gallium nitride (GaN) layer;
an n-doped semiconductor layer comprising a Si-doped n-GaN layer and an InGaN shallow wells; and
a p-doped semiconductor layer comprising a Mg-doped p-GaN layer and a Mg-doped p-In 0.02 Ga 0.98 N layer stacked above the Mg-doped p-GaN layer.
7. The full-color LED micro-display of claim 2 , wherein the monochrome red LED structure further comprising:
an n-side layer comprising a Si-doped n-GaAs layer, a Si-doped n-AlGaInP layer, and a Si-doped n-AlInP layer; and
a p-side layer comprising a Zn or Mg doped p-AlInP layer and a Zn or Mg doped p-GaP layer,
wherein:
the red emitting MQWs active region is sandwiched between the n-side layer and the p-side layer; and
the red emitting MQWs active region comprises one or more red emitting AlGaInP quantum wells (QWs) sandwiched between two AlGaInP quantum barrier layers.
8. The full-color LED micro-display of claim 2 , wherein:
the blue/green dual wavelength LED structure further comprises an electron blocking layer (EBL);
the EBL further comprises one or more magnesium-doped (Mg-doped) Al x Ga 1−x N with a magnesium doping concentration between 1×10 17 cm −3 and 1×10 20 cm −3 , and In y Ga 1−y N layers; and
x is any value between 0.01 and 0.3 and y is any value between 0 and 0.3.
9. The full-color LED micro-display of claim 1 , wherein the dual wavelength MQWs active region and the red emitting MQWs active region are formed on two different epitaxial layers that are not overlapping vertically.
10. The full-color LED micro-display of claim 8 , wherein the dual wavelength MQWs active region is positioned at a lower vertical position closer to a substrate layer than the red emitting MQWs active region.
11. The full-color LED micro-display of claim 1 , wherein:
the blue/green dual wavelength LED structure further comprises an n-doped semiconductor layer and a p-doped semiconductor layer;
the monochrome red LED structure further comprises an n-side layer and a p-side layer;
the dual wavelength MQWs active region is sandwiched between the n-doped semiconductor layer and the p-doped semiconductor layer, wherein the p-doped semiconductor layer is positioned above the dual wavelength MQWs active region and the n-doped semiconductor layer; and
the red emitting MQWs active region is sandwiched between the n-side layer and the p-side layer, wherein the n-side layer is positioned above the red emitting MQWs active region and the p-side layer.
12. The full-color LED micro-display of claim 1 , wherein the first LED, the second LED, and the third LED are formed above a driver panel via a plurality of pixel bonding pads, wherein the driver panel is a CMOS driving chip, a thin-film transistor (TFT) driving backplane, a gate-in-panel (GIP) circuit, or other driver panels that comprise circuits on a panel substrate.
13. The full-color LED micro-display of claim 12 , wherein the dual wavelength MQWs active region is positioned at a lower vertical position closer to the driver panel than the red emitting MQWs active region.
14. The full-color LED micro-display of claim 12 , wherein:
the blue/green dual wavelength LED structure further comprising an n-doped semiconductor layer and a p-doped semiconductor layer;
the monochrome red LED structure further comprising an n-side layer and a p-side layer;
the dual wavelength MQWs active region is sandwiched between the n-doped semiconductor layer and the p-doped semiconductor layer, wherein the n-doped semiconductor layer is positioned above the dual wavelength MQWs active region and the p-doped semiconductor layer; and
the red emitting MQWs active region is sandwiched between the n-side layer and the p-side layer, wherein the n-side layer is positioned above the red emitting MQWs active region and the p-side layer.