Light emitting diode (LED) using three-dimensional gallium nitride (GaN) pillar structures
A method is provided for fabricating a light emitting diode (LED) using three-dimensional gallium nitride (GaN) pillar structures with planar surfaces. The method forms a plurality of GaN pillar structures, each with an n-doped GaN (n-GaN) pillar and planar sidewalls perpendicular to the c-plane, formed in either an m-plane or a-plane family. A multiple quantum well (MQW) layer is formed overlying the n-GaN pillar sidewalls, and a layer of p-doped GaN (p-GaN) is formed overlying the MQW layer. The plurality of GaN pillar structures are deposited on a first substrate, with the n-doped GaN pillar sidewalls aligned parallel to a top surface of the first substrate. A first end of each GaN pillar structure is connected to a first metal layer. The second end of each GaN pillar structure is etched to expose the n-GaN pillar second end and connected to a second metal layer.
1. A method for fabricating a light emitting diode (LED) using three-dimensional gallium nitride (GaN) pillar structures with planar surfaces, the method comprising:
growing an n-doped GaN (n-GaN) film overlying a substrate;
forming a plurality of openings in a first region of the n-GaN film, each opening having planar sidewalls perpendicular to a c-plane aligned with a top surface of the n-GaN film, and formed in a plane selected from a group consisting of an in-plane and a-plane family;
forming a multiple quantum well (MQW) layer overlying the first region of n-GaN film, including the planar sidewalls of the openings;
forming a layer of p-doped GaN (p-GaN) overlying the MQW layer;
depositing a first metal layer overlying a second region of the n-GaN film forming a first electrode; and,
depositing a second metal layer overlying the p-GaN film to form a second electrode.
2. The method of claim 1 wherein forming the plurality of openings in the n-GaN film includes forming openings having a hexagonal shape.
3. The method of claim 1 wherein forming the plurality of openings in the n-GaN film includes:
forming cavities in the top surface of the n-GaN film;
wet etching the cavities in the n-GaN film top surface; and,
forming planar sidewalls extending into the n-GaN film.
4. A light emitting diode (LED) with three-dimensional gallium nitride (GaN) pillar structures having planar surfaces, the LED comprising:
an n-doped GaN (n-GaN) film overlying a substrate, having a first region with a plurality of openings and a second region, each opening having planar sidewalls perpendicular to a c-plane aligned with a top surface of the n-GaN film, and formed in a plane selected from a group consisting of a m-plane family and an a-plane family;
a multiple quantum well (MQW) layer overlying the n-GaN film first region, including the planar sidewalls of the openings;
a layer of p-doped GaN (p-GaN) overlying the MQW layer;
a first metal layer overlying the second region of n-GaN film forming a first electrode; and,
a second metal layer overlying the p-GaN film to form a second electrode.
5. The LED of claim 4 wherein the plurality of openings in the n-GaN film each have a hexagonal shape.
6. The method of claim 3 wherein forming cavities in the top surface of the n-GaN film includes using a process selects from a group consisting of plasma dry etching and laser ablation.
7. A method for fabricating a light emitting diode (LED) using three-dimensional gallium nitride (GaN) pillar structures with planar surfaces, the method comprising:
growing an n-doped GaN (n-GaN) film overlying a substrate;
generating a pattern of dislocation defects in a top surface of the n-GaN film;
wet etching the dislocation defects in the n-GaN film to remove n-GaN material damages in response to forming the dislocation defects;
stopping the removal of n-GaN material in response to encountering planes selected from a group consisting of c-planes, m-planes, and a-planes;
forming a plurality of openings in a first region of the n-GaN film, each opening having planar sidewalls perpendicular to a c-plane aligned with a top surface of the n-GaN film, and formed in a plane selected from a group consisting of an in-plane and a-plane family;
forming a multiple quantum well (MQW) layer overlying the first region of n-GaN film, including the planar sidewalls of the openings;
forming a layer of p-doped GaN (p (a) overlying the MQW layer;
depositing a first metal layer overlying a second region of the n-GaN film forming a first electrode; and,
depositing a second metal layer overlying the p-GaN film to form a second electrode.
8. The method of claim 7 wherein forming the plurality of openings in the n-GaN film includes forming openings having a hexagonal shape.
9. The method of claim 7 wherein forming dislocation defects in the top surface of the n-GaN film includes using a process selects from a group consisting of plasma dry etching and laser ablation.