US5739554A — Double heterojunction light emitting diode with g…

Claim 1

Independent Claim 143 words

A double heterostructure with p-n junction for a light emitting diode, said heterostructure comprising: a layer of aluminum gallium nitride having a first conductivity type; a layer of aluminum gallium nitride having the opposite conductivity type; an active layer consisting of gallium nitride between said aluminum gallium nitride layers, said gallium nitride layer being codoped with both a Group II acceptor and a Group IV donor, with one of said dopants being present in an amount greater than the other and sufficient to give said gallium nitride active layer a net conductivity type; said co-doped gallium nitride active layer forming a p-n junction with the adjacent layer of aluminum gallium nitride having the opposite conductivity type from said codoped gallium nitride active layer; and said double heterostructure producing a radiant flux of at least 100 microwatts at a forward current of 20 milliamps.

Claim 2

Dependent Claim 143 words

A double heterostructure with p-n junction for a light emitting diode, said heterostructure comprising: a layer of aluminum gallium nitride having a first conductivity type; a layer of aluminum gallium nitride having the opposite conductivity type; an active layer consisting of gallium nitride between said aluminum gallium nitride layers, said gallium nitride layer being codoped with both a Group II acceptor and a Group IV donor, with one of said dopants being present in an amount greater than the other and sufficient to give said gallium nitride active layer a net conductivity type; said co-doped gallium nitride active layer forming a p-n junction with the adjacent layer of aluminum gallium nitride having the opposite conductivity type from said codoped gallium nitride active layer; and said double heterostructure producing a radiant flux of at least 100 microwatts at a forward current of 20 milliamps.

Claim 3

Dependent Claim 14 words

A double heterostructure according to claim 1 wherein said gallium nitride layer is n-type.

Claim 4

Dependent Claim 21 words

A double heterostructure according to claim 1 wherein said Group II acceptor is zinc and said Group IV donor is silicon.

Claim 5

Dependent Claim 85 words

A double heterostructure with p-n junction for a light emitting diode, said heterostructure comprising: a p-type layer of aluminum gallium nitride; an n-type layer of aluminum gallium nitride; an n-type layer consisting of gallium nitride between said aluminum gallium nitride layers, said gallium nitride layer being codoped with both zinc and silicon and forming a p-n junction with said p-type layer of aluminum gallium nitride and said double heterostructure producing a radiant flux of at least 100 microwatts at a forward current of 20 milliamps.

Claim 6

Dependent Claim 85 words

A double heterostructure with p-n junction for a light emitting diode, said heterostructure comprising: a p-type layer of aluminum gallium nitride; an n-type layer of aluminum gallium nitride; an n-type layer consisting of gallium nitride between said aluminum gallium nitride layers, said gallium nitride layer being codoped with both zinc and silicon and forming a p-n junction with said p-type layer of aluminum gallium nitride and said double heterostructure producing a radiant flux of at least 100 microwatts at a forward current of 20 milliamps.

Claim 7

Dependent Claim 39 words

A double heterostructure according to claim 4 that consistently produces an emission with a peak wavelength of about 430 nanometers and a bandwith at half maximum of about 65 nm when a current is applied across said p-n junction.

Claim 8

Dependent Claim 25 words

A double heterostructure according to claim 4 wherein said n-type layer of aluminum gallium nitride has the formula Al x Ga 1-x N where 1>X>0.

Claim 9

Dependent Claim 12 words

A double heterostructure according to claim 6 wherein X is about 0.1.

Claim 10

Dependent Claim 25 words

A double heterostructure according to claim 4 wherein said p-type layer of aluminum gallium nitride has the formula Al x Ga 1-x N where 1>X>0.

Claim 11

Dependent Claim 12 words

A double heterostructure according to claim 8 wherein X is about 0.1.

Claim 12

Dependent Claim 24 words

A double heterostructure according to claim 4 wherein the n-type gallium nitride layer has a net doping density of between about 1E18 and 4E18.

Claim 13

Dependent Claim 21 words

A double heterostructure according to claim 4 wherein the p-type gallium nitride layer has a net doping density of about 1E19.

Claim 14

Dependent Claim 22 words

A double heterostructure according to claim 4 wherein the n-type aluminum gallium nitride layer has a net doping density of about 2E18.

Claim 15

Dependent Claim 25 words

A double heterostructure according to claim 4 wherein said gallium nitride active layer is compensated with a Group II acceptor and a Group IV donor.

Claim 16

Dependent Claim 27 words

A double heterostructure according to claim 13 wherein said Group II acceptor comprises zinc or cadmium or magnesium, and said Group IV donor comprises silicon or germanium.

Claim 17

Dependent Claim 22 words

A double heterostructure according to claim 4 wherein said gallium nitride active layer is compensated with carbon as a Group IV acceptor.

Claim 18

Dependent Claim 114 words

A double heterostructure light emitting diode with p-n junction that emits in the blue portion of the visible spectrum and comprising: a substrate; a buffer layer on said substrate; and a double heterostructure on said buffer layer, said double heterostructure comprising: an n-type layer of aluminum gallium nitride; an active layer consisting of compensated n-type gallium nitride on said n-type aluminum gallium nitride layer; and a p-type layer of aluminum gallium nitride on said gallium nitride layer, said p-type layer of aluminum gallium nitride and said compensated n-type gallium nitride active layer forming a pn junction; said diode producing a radiant flux of at least 100 microwatts at a forward current of 20 milliamps.

Claim 19

Dependent Claim 114 words

A double heterostructure light emitting diode with p-n junction that emits in the blue portion of the visible spectrum and comprising: a substrate; a buffer layer on said substrate; and a double heterostructure on said buffer layer, said double heterostructure comprising: an n-type layer of aluminum gallium nitride; an active layer consisting of compensated n-type gallium nitride on said n-type aluminum gallium nitride layer; and a p-type layer of aluminum gallium nitride on said gallium nitride layer, said p-type layer of aluminum gallium nitride and said compensated n-type gallium nitride active layer forming a pn junction; said diode producing a radiant flux of at least 100 microwatts at a forward current of 20 milliamps.

Claim 20

Dependent Claim 25 words

A double heterostructure light emitting diode according to claim 16 further comprising respective ohmic contacts to said substrate and said p-type aluminum gallium nitride layer.

Claim 21

Dependent Claim 19 words

A double heterostructure light emitting diode according to claim 16 wherein said ohmic contact to said substrate comprises nickel.

Claim 22

Dependent Claim 21 words

A double heterostructure light emitting diode according to claim 16 wherein said ohmic contact to said substrate comprises nickel and vanadium.

Claim 23

Dependent Claim 42 words

A double heterostructure light emitting diode according to claim 16 that consistently produces an emission with a peak wavelength of about 430 nanometers and a bandwith at half maximum of about 65 nm when a current is applied across said p-n junction.

Claim 24

Dependent Claim 23 words

A double heterostructure light emitting diode according to claim 16 and further comprising an n-type gallium nitride epitaxial layer on said buffer layer.

Claim 25

Dependent Claim 29 words

A double heterostructure light emitting diode according to claim 21 wherein said n-type layer of aluminum gallium nitride in said heterostructure is on said n-type gallium nitride epitaxial layer.

Claim 26

Dependent Claim 30 words

A double heterostructure light emitting diode according to claim 16 and further comprising a p-type layer of gallium nitride on said p-type layer of aluminum gallium nitride in said heterostructure.

Claim 27

Dependent Claim 23 words

A double heterostructure light emitting diode according to claim 23 and further comprising an ohmic contact to said p-type layer of gallium nitride.

Claim 28

Dependent Claim 37 words

A double heterostructure light emitting diode according to claim 24 wherein said ohmic contact to said p-type gallium nitride layer is selected from the group consisting of titanium alloyed with gold, nickel, and nickel alloyed with gold.

Claim 29

Dependent Claim 17 words

A double heterostructure light emitting diode according to claim 16 wherein said substrate comprises conductive silicon carbide.

Claim 30

Dependent Claim 28 words

A double heterostructure light emitting diode according to claim 16 wherein said n-type layer of aluminum gallium nitride as the formula Al x Ga 1-x N where 1>X>0.

Claim 31

Dependent Claim 15 words

A double heterostructure light emitting diode according to claim 27 wherein X is about 0.1.

Claim 32

Dependent Claim 28 words

A double heterostructure light emitting diode according to claim 16 wherein said p-type layer of aluminum gallium nitride has the formula Al x Ga 1-x N where 1>X>0.

Claim 33

Dependent Claim 15 words

A double heterostructure light emitting diode according to claim 29 wherein X is about 0.1.

Claim 34

Dependent Claim 22 words

A double heterostructure light emitting diode according to claim 16 wherein said gallium nitride layer is co-doped with both zinc and silicon.

Claim 35

Dependent Claim 21 words

A double heterostructure light emitting diode according to claim 16 wherein said gallium nitride layer includes carbon as an acceptor dopant.

Claim 36

Dependent Claim 27 words

A double heterostructure light emitting diode according to claim 16 wherein the n-type gallium nitride layer has a net doping density of between about 1E18 and 4E18.

Claim 37

Dependent Claim 24 words

A double heterostructure light emitting diode according to claim 16 wherein the p-type gallium nitride layer has a net doping density of about 1E19.

Claim 38

Dependent Claim 27 words

A double heterostructure light emitting diode according to claim 16 wherein the n-type aluminum gallium nitride layer has a net doping density of about 2E18 (Si doped).

Claim 39

Dependent Claim 66 words

A double heterostructure light emitting diode according to claim 16 wherein said buffer layer comprises: a first layer of gallium nitride and aluminum nitride; and a second layer of gallium nitride and aluminum nitride adjacent to said first layer, and in which the mole percentage of aluminum nitride in said second layer is substantially different from the mole percentage of aluminum nitride in said first layer.

Claim 40

Dependent Claim 60 words

A double heterostructure light emitting diode according to claim 16 wherein said buffer layer comprises a graded layer of aluminum gallium nitride that is substantially entirely aluminum nitride where it meets said substrate and then is progressively graded with increasing amounts of gallium until it is substantially entirely gallium nitride at its upper surface where it meets said double heterostructure.

Claim 41

Dependent Claim 118 words

A double heterostructure light emitting diode according to claim 16 wherein said buffer layer comprises a conductive layer selected from the group consisting of gallium nitride, aluminum nitride, indium nitride, ternary Group III nitrides having the formula A x B 1-x N, where A and B are Group III elements and where x is zero, one, or a fraction between zero and one, quaternary Group III nitrides having the formula A x B y C 1-x-y N where A, B, and C are Group III elements; x and y, are zero, one, or a fraction between zero and one, and 1 is greater than (x+y), and alloys of silicon carbide with such ternary and quaternary Group III nitrides.

Claim 42

Dependent Claim 93 words

A double heterostructure light emitting diode according to claim 16 wherein said buffer layer comprises a first layer upon said substrate formed of a graded composition of silicon carbide aluminum gallium nitride in which the portion adjacent the substrate is substantially entirely silicon carbide and the portion furthest from the substrate is substantially entirely aluminum gallium nitride with the portions therebetween being progressively graded in content from predominantly silicon carbide to predominantly aluminum gallium nitride; and a second layer upon said first layer and formed of a graded composition of aluminum gallium nitride.

Claim 43

Dependent Claim 28 words

A double heterostructure light emitting diode according to claim 16 wherein said gallium nitride active layer is compensated with a Group II acceptor and a Group IV donor.

Claim 44

Dependent Claim 30 words

A double heterostructure light emitting diode according to claim 40 wherein said Group II acceptor comprises zinc or cadmium or magnesium, and said Group IV donor comprises silicon or germanium.

Claim 45

Dependent Claim 28 words

A double heterostructure light emitting diode according to claim 16 wherein said buffer layer is insulating, and further comprising shorting contacts between said substrate and said double heterostructure.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2001-04-13	2001-10-13	2002-04-14	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2005-04-13	2005-10-13	2006-04-14	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2009-04-13	2009-10-13	2010-04-14	$7700.00	Window Closed / Lapsed

Double heterojunction light emitting diode with gallium nitride active layer

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