US5422902A — BeTe-ZnSe graded band gap ohmic contact to p-type…

Claim 1

Independent Claim 93 words

An ohmic contact joining a metal member to a Group II-VI compound semiconductor device which comprises a substrate, said contact comprising a layer consisting essentially of a BeTe-containing material effective to reduce the valence band affinity of the semiconductor near the surface, said layer of BeTe-containing material consisting essentially of a graded composition of Be x Zn 1-x Te x Se 1-x wherein x is within the range of 0 and 1 selected so as to provide a lattice structure in said graded composition that matches substantially the lattice structure of the substrate.

Claim 2

Dependent Claim 93 words

An ohmic contact joining a metal member to a Group II-VI compound semiconductor device which comprises a substrate, said contact comprising a layer consisting essentially of a BeTe-containing material effective to reduce the valence band affinity of the semiconductor near the surface, said layer of BeTe-containing material consisting essentially of a graded composition of Be x Zn 1-x Te x Se 1-x wherein x is within the range of 0 and 1 selected so as to provide a lattice structure in said graded composition that matches substantially the lattice structure of the substrate.

Claim 3

Dependent Claim 32 words

An Ohmic contact as claimed in claim 1 wherein said contact has a contact resistivity lower than p c =10 -4 Ωcm 2 at acceptor doping level 1×10 18 cm -3 .

Claim 4

Dependent Claim 27 words

An Ohmic contact as claimed in claim 1 wherein said graded composition is obtained by molecular beam epitaxial growth of alternately grown layers of BeTe and ZnSe.

Claim 5

Dependent Claim 33 words

An ohmic contact as claimed in claim 3 wherein the graded composition comprises a BeTe top layer grown on a series of layers wherein the parameter x gradually changes from 1 to 0.

Claim 6

Dependent Claim 28 words

An ohmic contact as claimed in claim 3 wherein said layer of graded BeTe-containing material includes a region around a BeTe/ZnSe junction having a width w j .

Claim 7

Dependent Claim 25 words

An ohmic contact as claimed in claim 5 wherein said region is divided into a series of segments (BeTe) x and (ZnSe) 1-x grown alternately.

Claim 8

Dependent Claim 69 words

An ohmic contact as claimed in claim 6 in which there are a plurality of segments each having a width of 40 A, the value of x varying from 1 to 0 from the top segment to the bottom segment and the thickness of the BeTe content of the segment decreasing and the ZnSe content increasing in increments of 2 A from the top segment to the bottom segment.

Claim 9

Dependent Claim 50 words

An ohmic contact as claimed in claim 6 in which there are a plurality of segments, the content of each segment being alternately multiple monolayers of BeTe and ZnSe and mixtures thereof, graded from a top segment of multiple monolayers of BeTe to a bottom segment of monolayers of ZnSe.

Claim 10

Dependent Claim 97 words

A II-VI compound diode laser structure comprising an ohmic contact joining a metal member to a Group II-VI compound semiconductor body including a substrate, said contact comprising a layer consisting essentially of a BeTe-containing material effective to reduce the valence band affinity of the semiconductor near the surface; said layer being epitaxially grown on said semiconductor body, being substantially entirely lattice matched to the substrate, and consisting essentially of Be x Zn 1-x Te x Se 1-x wherein x is within the range of 0 and 1 selected so as to provide lattice matching to the substrate.

Claim 11

Dependent Claim 97 words

A II-VI compound diode laser structure comprising an ohmic contact joining a metal member to a Group II-VI compound semiconductor body including a substrate, said contact comprising a layer consisting essentially of a BeTe-containing material effective to reduce the valence band affinity of the semiconductor near the surface; said layer being epitaxially grown on said semiconductor body, being substantially entirely lattice matched to the substrate, and consisting essentially of Be x Zn 1-x Te x Se 1-x wherein x is within the range of 0 and 1 selected so as to provide lattice matching to the substrate.

Claim 12

Dependent Claim 32 words

A laser structure as claimed in claim 9 wherein said contact has a contact resistivity lower than p c =10 -4 Ωcm 2 at acceptor doping level 1×10 18 cm -3 .

Claim 13

Dependent Claim 27 words

A laser structure as claimed in claim 9 wherein said graded composition is obtained by molecular beam epitaxial growth of alternately grown layers of BeTe and ZnSe,

Claim 14

Dependent Claim 33 words

A laser structure as claimed in claim 11 wherein the graded composition comprises a BeTe top layer grown on a series of layers wherein the parameter x gradually changes from 1 to 0.

Claim 15

Dependent Claim 28 words

A laser structure as claimed in claim 11 wherein said layer of graded BeTe-containing material includes a region around a BeTe/ZnSe junction having a width w j .

Claim 16

Dependent Claim 25 words

A laser structure as claimed in claim 13 wherein said region is divided into a series of segments (BeTe) x and (ZnSe) 1-x grown alternately.

Claim 17

Dependent Claim 69 words

A laser structure as claimed in claim 14 in which there are a plurality of segments each having a width of 40 A, the value of x varying from 1 to 0 from the top segment to the bottom segment and the thickness of the BeTe content of the segment decreasing and the ZnSe content increasing in increments of 2 A from the top segment to the bottom segment.

Claim 18

Dependent Claim 50 words

A laser structure as claimed in claim 14 in which there are a plurality of segments, the content of each segment being alternately multiple monolayers of BeTe and ZnSe and mixtures thereof, graded from a top segment of multiple monolayers of BeTe to a bottom segment of monolayers of ZnSe.

Claim 19

Dependent Claim 128 words

A laser structure comprising: (a) a substrate of a first conductivity type; (b) a cladding layer of first conductivity type disposed atop said substrate; (c) a guiding layer of said first conductivity type disposed atop said first conductivity type cladding layer; (d) an active layer disposed atop said first conductivity type guiding layer; (e) a guiding layer of a second conductivity type opposite said first conductivity type, disposed atop said active layer; (f) a cladding layer of said second conductivity type; and (g) an ohmic contact layer of BeTe-containing graded composition which consists essentially of Be x Zn 1-x Te x Se 1-x wherein x is within the range of 0 and 1 selected so as to provide substantial lattice matching to the lattice structure of the substrate.

Claim 20

Dependent Claim 128 words

A laser structure comprising: (a) a substrate of a first conductivity type; (b) a cladding layer of first conductivity type disposed atop said substrate; (c) a guiding layer of said first conductivity type disposed atop said first conductivity type cladding layer; (d) an active layer disposed atop said first conductivity type guiding layer; (e) a guiding layer of a second conductivity type opposite said first conductivity type, disposed atop said active layer; (f) a cladding layer of said second conductivity type; and (g) an ohmic contact layer of BeTe-containing graded composition which consists essentially of Be x Zn 1-x Te x Se 1-x wherein x is within the range of 0 and 1 selected so as to provide substantial lattice matching to the lattice structure of the substrate.

Claim 21

Dependent Claim 96 words

An ohmic contact joining a metal member to a Group II-VI compound semiconductor device containing p-ZnSe and a GaAs substrate, said contact comprising a layer consisting essentially of a p-BeTe-containing material effective to reduce the valence band affinity of the semiconductor near the surface, said layer of BeTe-containing material consisting essentially of a graded composition of Be x Zn 1-x Te x Se 1-x wherein x is within the range of 0 and 1 selected so as to provide a lattice structure in said graded composition that matches substantially the lattice structure of the p-GaAs substrate.

Claim 22

Dependent Claim 96 words

An ohmic contact joining a metal member to a Group II-VI compound semiconductor device containing p-ZnSe and a GaAs substrate, said contact comprising a layer consisting essentially of a p-BeTe-containing material effective to reduce the valence band affinity of the semiconductor near the surface, said layer of BeTe-containing material consisting essentially of a graded composition of Be x Zn 1-x Te x Se 1-x wherein x is within the range of 0 and 1 selected so as to provide a lattice structure in said graded composition that matches substantially the lattice structure of the p-GaAs substrate.

Claim 23

Dependent Claim 32 words

An Ohmic contact as claimed in claim 18 wherein said contact has a contact resistivity lower than p c =10 -4 Ωcm 2 at acceptor doping level 1×10 18 cm -3 .

Claim 24

Dependent Claim 27 words

An Ohmic contact as claimed in claim 18 wherein said graded composition is obtained by molecular beam epitaxial growth of alternately grown layers of BeTe and ZnSe.

Claim 25

Dependent Claim 33 words

An ohmic contact as claimed in claim 20 wherein the graded composition comprises a BeTe top layer grown on a series of layers wherein the parameter x gradually changes from 1 to 0.

Claim 26

Dependent Claim 28 words

An ohmic contact as claimed in claim 20 wherein said layer of graded BeTe-containing material includes a region around a BeTe/ZnSe junction having a width w j .

Claim 27

Dependent Claim 25 words

An ohmic contact as claimed in claim 22 wherein said region is divided into a series of segments (BeTe) x and (ZnSe) 1-x grown alternately.

Claim 28

Dependent Claim 69 words

An ohmic contact as claimed in claim 23 in which there are a plurality of segments each having a width of 40 A, the value of x varying from 1 to 0 from the top segment to the bottom segment and the thickness of the BeTe content of the segment decreasing and the ZnSe content increasing in increments of 2 A from the top segment to the bottom segment.

Claim 29

Dependent Claim 51 words

An ohmic contact as claimed in claim 23 in which there are a plurality of segments, the content of each segment being alternately multiple monolayers of (BeTe) and (ZnSe) and mixtures thereof, graded from a top segment of multiple monolayers of (BeTe) to a bottom segment of monolayers of (ZnSe) .

Claim 30

Dependent Claim 95 words

A II-VI compound diode laser structure comprising an ohmic contact joining a metal member to a Group II-VI compound semiconductor body containing ZnSe and including a GaAs substrate, said contact comprising a layer consisting essentially of a BeTe-containing material effective to reduce the valence band affinity of the semiconductor near the surface; said layer being substantially entirely lattice matched to the substrate, and consisting essentially of Be x Zn 1-x Te x Se 1-x wherein x is within the range of 0 and 1 selected so as to provide said lattice matching to the substrate.

Claim 31

Dependent Claim 95 words

A II-VI compound diode laser structure comprising an ohmic contact joining a metal member to a Group II-VI compound semiconductor body containing ZnSe and including a GaAs substrate, said contact comprising a layer consisting essentially of a BeTe-containing material effective to reduce the valence band affinity of the semiconductor near the surface; said layer being substantially entirely lattice matched to the substrate, and consisting essentially of Be x Zn 1-x Te x Se 1-x wherein x is within the range of 0 and 1 selected so as to provide said lattice matching to the substrate.

Claim 32

Dependent Claim 30 words

A laser structure as claimed in claim 26 wherein said contact has a contact resistivity lower than ρ=10 -4 Ωcm 2 at acceptor doping level 1×10 18 cm -3 .

Claim 33

Dependent Claim 27 words

A laser structure as claimed in claim 27 wherein said graded composition is obtained by molecular beam epitaxial growth of alternately grown layers of BeTe and ZnSe.

Claim 34

Dependent Claim 33 words

A laser structure as claimed in claim 28 wherein the graded composition comprises a BeTe top layer grown on a series of layers wherein the parameter x gradually changes from 1 to 0.

Claim 35

Dependent Claim 28 words

A laser structure as claimed in claim 26 wherein said layer of graded BeTe-containing material includes a region around a BeTe/ZnSe junction having a width w j .

Claim 36

Dependent Claim 25 words

A laser structure as claimed in claim 30 wherein said region is divided into a series of segments (BeTe) x and (ZnSe) 1-x grown alternately.

Claim 37

Dependent Claim 69 words

A laser structure as claimed in claim 30 in which there are a plurality of segments each having a width of 40 A, the value of x varying from 1 to 0 from the top segment to the bottom segment and the thickness of the BeTe content of the segment decreasing and the ZnSe content increasing in increments of 2 A from the top segment to the bottom segment.

Claim 38

Dependent Claim 50 words

A laser structure as claimed in claim 32 in which there are a plurality of segments, the content of each segment being alternately multiple monolayers of (BeTe) and (ZnSe) and mixtures thereof, graded from a top segment of multiple monolayers of (BeTe) to a bottom segment of monolayers of (ZnSe).

Claim 39

Dependent Claim 108 words

A laser structure comprising: (a) an n-GaAs substrate; (b) a n-ZnSe-containing cladding layer disposed atop said GaAs substrate; (c) a n-ZnSe guiding layer disposed atop said n-ZnSe-containing cladding layer; (d) an active layer disposed atop said n-ZnSe guiding layer; (e) a p-ZnSe guiding layer disposed atop said active layer; (f) a p-ZnSe-containing cladding layer disposed atop said p-ZnSe guiding layer; and (g) an ohmic contact layer of BeTe-containing graded composition which consists essentially of Be x Zn 1-x Te x Se 1-x wherein x is within the range of 0 and 1 selected so as to provide substantial lattice matching to the lattice structure of the n-GaAs substrate.

Claim 40

Dependent Claim 108 words

A laser structure comprising: (a) an n-GaAs substrate; (b) a n-ZnSe-containing cladding layer disposed atop said GaAs substrate; (c) a n-ZnSe guiding layer disposed atop said n-ZnSe-containing cladding layer; (d) an active layer disposed atop said n-ZnSe guiding layer; (e) a p-ZnSe guiding layer disposed atop said active layer; (f) a p-ZnSe-containing cladding layer disposed atop said p-ZnSe guiding layer; and (g) an ohmic contact layer of BeTe-containing graded composition which consists essentially of Be x Zn 1-x Te x Se 1-x wherein x is within the range of 0 and 1 selected so as to provide substantial lattice matching to the lattice structure of the n-GaAs substrate.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1998-06-05	1998-12-05	1999-06-06	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2002-06-05	2002-12-05	2003-06-06	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2006-06-05	2006-12-05	2007-06-06	$7700.00	Window Closed / Lapsed

BeTe-ZnSe graded band gap ohmic contact to p-type ZnSe semiconductors

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