High brightness electroluminescent device emitting in the green to ultraviolet spectrum and method of making the same
AssigneeAdvanced Technology Materials, Inc.
InventorsJoan Redwing, Michael A. Tischler
Life of this patent
Estimating the term…
Abstract
A green-blue to ultraviolet light emitting semiconductor laser having a top contact, a Bragg reflector, cladding layer, active layer, cladding layer, buffer, substrate, bottom contact and a passivation layer. The key aspect is a Ga*N material on a base structure comprising a SiC substrate selected from a group consisting of 2H-SiC, 4H-SiC and a-axis oriented 6H-SiC. Furthermore, the cladding layers have larger band gaps than the active layer and are complimentarily doped.
Claims32
A semiconductor device or precursor thereof, comprising a layer of single crystal silicon carbide and a layer of single crystal gallium nitride, having a buffer layer therebetween comprising a compositionally graded Ga*N layer.
A semiconductor device or precursor thereof, comprising a silicon carbide substrate and an epitaxial layer of gallium nitride, having a buffer layer therebetween comprising a compositionally graded (Al,Ga)N buffer layer.
A semiconductor device or precursor thereof, comprising a silicon carbide substrate and an epitaxial layer of gallium nitride, having a buffer material therebetween comprising an AlN buffer layer on the silicon carbide substrate, and a compositionally graded (Al,Ga)N buffer layer between the AlN buffer layer and the gallium nitride epitaxial layer.
A semiconductor device or precursor thereof, comprising a silicon carbide substrate and an epitaxial layer of gallium nitride, having a buffer material therebetween comprising a conductive buffer layer of the formula Al.sub.x Ga.sub.1-x N wherein the buffer layer includes a lower Al composition layer that is doped to render it highly conductive in character.
A semiconductor device or precursor thereof, comprising a silicon carbide substrate and an epitaxial layer of gallium nitride, having a buffer material therebetween comprising a buffer layer selected from the group consisting of (Al, Ga)N compositionally graded layers, (Al, In)N compositionally graded layers, and (Al, Ga, In)N compositionally graded layers.
A semiconductor device or precursor thereof, comprising a SiC substrate element including a mesa-shaped portion having a Ga*N quantum well structure or other Ga*N s tructure formed thereon, where in t he mesa-shaped portion has an equivalent diameter in the range of from 50 to 300 .mu.m, and a height of from 1 to 15 .mu.m.
A method for fabricating a light emitting diode comprising the steps of:
- a. forming an M.sub.x M'.sub.y M".sub.1-x-y N barrier layer on a conductive substrate, wherein M, M', and M" are metals compatible with nitrogen (N) in the composition M.sub.x M'.sub.y M".sub.1-x-y N, and the composition M.sub.x M'.sub.y M".sub.1-x-y N is stable at room temperatures and pressures;
- b. forming an M.sub.a M'.sub.b M".sub.1-a-b N active region on the M.sub.x M'.sub.y M".sub.1-x-y N barrier layer;
- c. forming an M.sub.c M'.sub.d M".sub.1-c-d N barrier layer on the M.sub.a M'.sub.b M".sub.1-a-b N active region;
- d. forming a heavily doped contact layer on the M.sub.c M'.sub.d M".sub.1-c-d N barrier layer;
- and
- e. forming a first contact on the heavily doped contact layer and a second contact on the substrate, wherein x, y, a, b, c, and d are numbers, each number having a magnitude between zero and one and wherein x+y, a+b, and c+d, each have a magnitude between zero and one.
A method for fabricating a light emitting diode comprising the steps of:
- a. forming a first barrier layer on a conductive substrate, the first barrier layer being a first selected composition;
- b. forming an active region of a second selected composition on the first barrier layer;
- C. forming a second barrier layer of a third selected composition on the active region;
- d. forming a heavily doped contact layer of a fourth selected composition on the second barrier layer;
- and
- e. forming a first contact on the heavily doped contact layer and a second contact on the substrate, wherein the first, second, third and fourth selected compositions are selected from a group of compositions M.sub.x M'.sub.y M".sub.1-x-y N, M.sub.a M'.sub.b M".sub.1-a-b N, M.sub.c M'.sub.d M".sub.1-c-d N and M.sub.e M'.sub.f M".sub.1-e-f N, respectively, wherein x, y, a, b, c, d, e, and f are numbers, each number having a magnitude between zero and one and wherein x+y, a+b, c+d, and e+f, each has a magnitude between zero and one.
The method for fabricating a light emitting diode with a Bragg mirror, the method comprising the steps of:
- a. forming a Bragg mirror including alternating layers of AlN, GaN, InN, or their alloys on a conductive substrate;
- b. forming an M.sub.x M'.sub.y M".sub.1-x-y N barrier layer on a conductive substrate, wherein M, M', and M" are metals compatible with nitrogen (N) in the composition M.sub.x M'.sub.y M".sub.1-x-y N, and the composition M.sub.x M'.sub.y M".sub.1-x-y N is stable at room temperatures and pressures;
- c. forming an M.sub.a M'.sub.b M".sub.1-a-b N active region on the M.sub.x M'.sub.y M".sub.1-x-y N barrier layer;
- d. forming an M.sub.c M'.sub.d M".sub.1-c-d N barrier layer on the M.sub.a M'.sub.b M".sub.1-a-b N active region;
- e. forming a heavily doped contact layer on the M.sub.c M'.sub.d M".sub.1-c-d N barrier layer;
- and
- f. forming a first contact on the heavily doped contact layer and a second contact on the substrate, wherein x, y, a, b, c, and d are numbers, each number having a magnitude between zero and one and wherein x+y, a+b, and c+d, each have a magnitude between zero and one.
The method for fabricating light emitting diodes (LEDs) comprising the steps of:
- a. forming a first barrier layer on a conductive substrate;
- b. forming an active region on the first barrier layer;
- C. forming a second barrier layer on the active region;
- d. forming a heavily doped contact layer on the second barrier layer;
- e. masking each LED device area;
- f. mesa etching trenches between the LED device areas and leaving the LEDs as mesas separated by the trenches;
- g. passivating sidewalls of the LEDs;
- h. forming a first contact on the heavily doped contact layer and a second contact on the substrate;
- and
- i. slicing the substrate only in the trenches.
Dependencies are inferred from the claim text.