Micro-LED structure and micro-LED chip including same
A micro-LED chip includes multiple micro-LEDs. At least one micro-LED of the multiple micro-LEDs includes: a first type conductive layer; a second type conductive layer stacked on the first type conductive layer; and a light emitting layer formed between the first type conductive layer and the second type conductive layer. The light emitting layer extends along a horizontal level from a top edge of the first type conductive layer and a bottom edge of the second type conductive layer. The micro-LED chip further includes a metal layer formed on a portion of the light emitting layer that extends from the second type conductive layer.
1. A micro-LED chip including multiple micro-LEDs, wherein,
at least one micro-LED of the multiple micro-LEDs comprises:
a first type conductive layer;
a second type conductive layer stacked on the first type conductive layer; and
a light emitting layer formed between the first type conductive layer and the second type conductive layer, wherein the light emitting layer extends along a horizontal level from a top edge of the first type conductive layer and a bottom edge of the second type conductive layer, such that an edge of the light emitting layer does not contact the top edge of the first type conductive layer and the bottom edge of the second type conductive layer, and a profile of the first type conductive layer perpendicularly projected on a bottom surface of the second type conductive layer is surrounded by the bottom edge of the second type conductive layer, and
the micro-LED chip further comprises a metal layer formed on a portion of the light emitting layer that extends from the second type conductive layer, wherein a bottom surface of the metal layer is horizontally aligned with a bottom surface of the second type conductive layer.
2. The micro-LED chip according to claim 1 , wherein the metal layer is formed on a surface of the light emitting layer and does not contact the first type conductive layer or the second type conductive layer.
3. The micro-LED chip according to claim 1 , wherein a lateral dimensional value of the metal layer is not more than a distance between an edge of the light emitting layer and the bottom edge of the second type conductive layer.
4. The micro-LED chip according to claim 3 , wherein the lateral dimensional value of the metal layer is from 2 nm to 10 um.
5. The micro-LED chip according to claim 1 , wherein a center point of the metal layer is aligned with a center point between the adjacent micro-LEDs.
6. The micro-LED chip according to claim 1 , wherein a center point of the metal layer is near one of the adjacent micro-LEDs.
7. The micro-LED chip according to claim 1 , wherein the metal layer comprises a plurality of metal layers, and the plurality of metal layers are arranged in parallel along a surface of the light emitting layer.
8. The micro-LED chip according to claim 1 , wherein a material of the metal layer includes a high work function metal material which matches a material of the light emitting layer.
9. The micro-LED chip according to claim 8 , wherein the high work function metal material includes at least one of gold, platinum, palladium, beryllium, cobalt, nickel, or tungsten.
10. The micro-LED chip according to claim 1 , wherein the light emitting layer is continuously formed on the micro-LED chip.
11. The micro-LED chip according to claim 1 , wherein the multiple micro-LEDs share the light emitting layer.
12. The micro-LED chip according to claim 1 , further comprising:
a top spacer formed on a top surface of the light emitting layer;
a bottom spacer formed on a bottom surface of the light emitting layer,
wherein an edge of the top spacer is aligned with an edge of the light emitting layer, and
an edge of the bottom spacer is aligned with the edge of the light emitting layer.
13. The micro-LED chip according to claim 12 , wherein a thickness of the top spacer is larger than a thickness of the light emitting layer, and a thickness of the bottom spacer is larger than the thickness of the light emitting layer.
14. The micro-LED chip according to claim 12 , further comprising, in the at least one micro-LED, a microlens formed on the second type conductive layer and on a top surface of the top spacer.
15. The micro-LED chip according to claim 1 , wherein a top area of the first type conductive layer is larger than a bottom area of the first type conductive layer, and a top area of the second type conductive layer is smaller than a bottom area of the second type conductive layer.
16. The micro-LED chip according to claim 1 , wherein the light emitting layer includes only one pair of quantum well layers, or multiple pairs of quantum well layers.
17. The micro-LED chip according to claim 1 , wherein the at least one micro-LED further comprises a reflective structure formed surrounding the first type conductive layer.
18. The micro-LED chip according to claim 17 , wherein, in the at least one micro-LED, the reflective structure is attached on a sidewall surface of the first type conductive layer, and
the at least one micro-LED further comprises a bottom connection structure formed under the first type conductive layer and electrically connected with the first type conductive layer.
19. The micro-LED chip according to claim 18 , further comprising a substrate under the first type conductive layer, and electrically connected with the bottom connection structure by a connecting pad in the substrate.
20. The micro-LED chip according to claim 18 , wherein the bottom connection structure is made of a reflective and electrically conductive material.