Patent
US 8,692,295TRANSISTOR WITH InGaAsP COLLECTOR REGION AND INTEGRATED OPTO-ELECTRONIC DEVICES EMPLOYING SAME
Rajesh D. RAJAVEL
US
Copyright © 2026 Matter42. All rights reserved.
Patent
Atlas literature
Patent
US 8,692,295Patent drawings and their descriptions. Click a drawing to enlarge it.
FIG. 1, a generic DHBT structure 10 is shown for discussion purposes. A transistor such as DHBT 10 is typically formed on a substrate 100, and includes a …
FIG. 2 is a graph depicting Poisson band bending models for the base collector interface for a baseline DHBT and a DHBT formed in accordance with the present …
FIG. 3 is a graph depicting the room temperature photoluminescence spectrum for an MBE-grown Ino.75Gao.25Aso.54Po.46 film deposited on InGaAs, in accordance …
FIG. 4 is a graph depicting the x-ray rocking curve for a DHBT using a lattice matched Ino.75Gao.25Aso.54Po.46 4 collector and a strained base layer, in …
FIG. 5 is a structural block diagram of an integrated opto-electronic device employing a DHBT formed in accordance with the present disclosure.
Claims define the patent's legal scope. Independent claims stand alone; dependent claims (nested) narrow them. Click a claim to expand its dependents.
A bipolar transistor on a substrate, comprising: a collector com p risin g In0Ga025As04 Po.46 having a first conductivity type; a base having a second conductivity type and in contact with the collector; an emitter of the first conductivity type in contact with the base; and electrodes forming separate electrical contacts with each of the collector, base, and emitter, respectively; and wherein the base is formed substantially of InGaAs having a composition having a conduction band energy level higher than Ino.5 3Ga 0. 47As.
The transistor of claim 1, wherein the collector includes a graded layer in contact with the base and varying in composition to minimize a conduction band discontinuity between the base and the collector.
The transistor of claim 1, wherein the collector includes a sub-layer in contact with the substrate and having a higher doping concentration than the rest of the collector.
The transistor of claim 1, further comprising: a sub-collector layer formed substantially of InGaAs of the first conductivity type and in contact with the collector.
The transistor of claim 1, wherein the conduction band energy level of the base at least in the vicinity of the base/collector junction is higher than the conduction band energy level of In o.5 3Ga 0. 47As.
The transistor of claim 1, wherein the Ga mole fraction in the base is above 0.47. U. S. A ppl n. No. 12/567,556 Pa ge 3
The transistor of claim 1, wherein the base is formed substantially of InGaAs or GaAsSb.
The transistor of claim 1, wherein the collector is configured to form a waveguide for light having a 1.5 micron wavelength.
The transistor of claim 1, wherein the collector is configured to form a waveguide for light. previously presented
The transistor of claim 1, wherein the base has a thickness of less than 500 Angstroms.
The transistor of claim 1, wherein: the base comprises In o. 44Ga 0s6As;-and th ltrmpiGa--As-s4-P.
canceled
A bipolar transistor on a substrate, comprising: a collector comprising Ino.75Gao.2sAso5 4 Po.46 having a first conductivity type; a base having a second conductivity type and in contact with the collector; an emitter of the first conductivity type in contact with the base; and electrodes forming separate electrical contacts with each of the collector, base, and emitter, respectively; and wherein the base comprises Ino. 44Ga 0s6 As. U. S. A ppl n. No. 12/567,556 Pa ge 4
The transistor of claim 14, wherein the collector comprises a graded layer in contact with the base and varying in composition to minimize a conduction band discontinuity between the base and the collector.
The transistor of claim 14, wherein the collector is configured to form a waveguide for light having a 1.5 micron wavelength.
The transistor of claim 14, wherein the collector is configured to form a waveguide for light.
The transistor of claim 14, wherein the base further comprises In0. 53Ga o. 47As.
The transistor of claim 14, wherein the base has a thickness of less than 500 Angstroms.
The transistor of claim 14 further comprising: a graded collector between the base and the collector to provide smooth grading in the conduction energy band between the base and the collector.
Embodiments described in the patent, grouped by the materials and process steps they use.
6 materials1 process step
A DHBT structure was grown by MBE with an In0.75Ga0.25As0.54P0.46 quaternary collector (~1500 Å, n:7E₁₆ cm⁻³), a coherently strained In0.44Ga0.56As base (~300 Å, p:3E₁₈ cm⁻³), a 450 Å graded InGaAsP collector layer transitioning between base and collector, and an InGaAs sub-collector. A dry-etch process was used to etch the quaternary collector. DC gain of ~25 was measured; collector breakdown voltage BVceo was as high as 6V for a 2000 Å thick collector; base-emitter turn-on voltage Vbe was 0.6V; reverse breakdown voltage was 2V. PL and x-ray measurements were used to confirm layer composition and lattice matching.
Layer stacks claimed or described, ordered top of device to substrate.
Double Heterojunction Bipolar Transistor (DHBT) — generic InGaAsP collector, high-Ga InGaAs base
Double Heterojunction Bipolar Transistor (DHBT) — In0.75Ga0.25As0.54P0.46 collector, In0.44Ga0.56As base
Materials described outside the worked examples.
GaAsSb
In0.53Ga0.47As
InGaAsP graded collector layer
Measurements and analyses referenced in the patent, with their drawing references.
FIG. 1, a generic DHBT structure 10 is shown for discussion purposes. A transistor such as DHBT 10 is typically formed on a substrate 100, and includes a …
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
Band gap of In0.75Ga0.25As0.54P0.46 collector layer | 0.9 eV | In0.75Ga0.25As0.54P0.46 |
DC current gain of fabricated DHBT |
Related documents with shared materials, methods, properties, or citations.
Patent
Atlas literature
Patent
US 8,692,295Patent drawings and their descriptions. Click a drawing to enlarge it.
FIG. 1, a generic DHBT structure 10 is shown for discussion purposes. A transistor such as DHBT 10 is typically formed on a substrate 100, and includes a …
FIG. 2 is a graph depicting Poisson band bending models for the base collector interface for a baseline DHBT and a DHBT formed in accordance with the present …
FIG. 3 is a graph depicting the room temperature photoluminescence spectrum for an MBE-grown Ino.75Gao.25Aso.54Po.46 film deposited on InGaAs, in accordance …
FIG. 4 is a graph depicting the x-ray rocking curve for a DHBT using a lattice matched Ino.75Gao.25Aso.54Po.46 4 collector and a strained base layer, in …
FIG. 5 is a structural block diagram of an integrated opto-electronic device employing a DHBT formed in accordance with the present disclosure.
Claims define the patent's legal scope. Independent claims stand alone; dependent claims (nested) narrow them. Click a claim to expand its dependents.
A bipolar transistor on a substrate, comprising: a collector com p risin g In0Ga025As04 Po.46 having a first conductivity type; a base having a second conductivity type and in contact with the collector; an emitter of the first conductivity type in contact with the base; and electrodes forming separate electrical contacts with each of the collector, base, and emitter, respectively; and wherein the base is formed substantially of InGaAs having a composition having a conduction band energy level higher than Ino.5 3Ga 0. 47As.
The transistor of claim 1, wherein the collector includes a graded layer in contact with the base and varying in composition to minimize a conduction band discontinuity between the base and the collector.
The transistor of claim 1, wherein the collector includes a sub-layer in contact with the substrate and having a higher doping concentration than the rest of the collector.
The transistor of claim 1, further comprising: a sub-collector layer formed substantially of InGaAs of the first conductivity type and in contact with the collector.
The transistor of claim 1, wherein the conduction band energy level of the base at least in the vicinity of the base/collector junction is higher than the conduction band energy level of In o.5 3Ga 0. 47As.
The transistor of claim 1, wherein the Ga mole fraction in the base is above 0.47. U. S. A ppl n. No. 12/567,556 Pa ge 3
The transistor of claim 1, wherein the base is formed substantially of InGaAs or GaAsSb.
The transistor of claim 1, wherein the collector is configured to form a waveguide for light having a 1.5 micron wavelength.
The transistor of claim 1, wherein the collector is configured to form a waveguide for light. previously presented
The transistor of claim 1, wherein the base has a thickness of less than 500 Angstroms.
The transistor of claim 1, wherein: the base comprises In o. 44Ga 0s6As;-and th ltrmpiGa--As-s4-P.
canceled
A bipolar transistor on a substrate, comprising: a collector comprising Ino.75Gao.2sAso5 4 Po.46 having a first conductivity type; a base having a second conductivity type and in contact with the collector; an emitter of the first conductivity type in contact with the base; and electrodes forming separate electrical contacts with each of the collector, base, and emitter, respectively; and wherein the base comprises Ino. 44Ga 0s6 As. U. S. A ppl n. No. 12/567,556 Pa ge 4
The transistor of claim 14, wherein the collector comprises a graded layer in contact with the base and varying in composition to minimize a conduction band discontinuity between the base and the collector.
The transistor of claim 14, wherein the collector is configured to form a waveguide for light having a 1.5 micron wavelength.
The transistor of claim 14, wherein the collector is configured to form a waveguide for light.
The transistor of claim 14, wherein the base further comprises In0. 53Ga o. 47As.
The transistor of claim 14, wherein the base has a thickness of less than 500 Angstroms.
The transistor of claim 14 further comprising: a graded collector between the base and the collector to provide smooth grading in the conduction energy band between the base and the collector.
Embodiments described in the patent, grouped by the materials and process steps they use.
6 materials1 process step
A DHBT structure was grown by MBE with an In0.75Ga0.25As0.54P0.46 quaternary collector (~1500 Å, n:7E₁₆ cm⁻³), a coherently strained In0.44Ga0.56As base (~300 Å, p:3E₁₈ cm⁻³), a 450 Å graded InGaAsP collector layer transitioning between base and collector, and an InGaAs sub-collector. A dry-etch process was used to etch the quaternary collector. DC gain of ~25 was measured; collector breakdown voltage BVceo was as high as 6V for a 2000 Å thick collector; base-emitter turn-on voltage Vbe was 0.6V; reverse breakdown voltage was 2V. PL and x-ray measurements were used to confirm layer composition and lattice matching.
Layer stacks claimed or described, ordered top of device to substrate.
Double Heterojunction Bipolar Transistor (DHBT) — generic InGaAsP collector, high-Ga InGaAs base
Double Heterojunction Bipolar Transistor (DHBT) — In0.75Ga0.25As0.54P0.46 collector, In0.44Ga0.56As base
Materials described outside the worked examples.
GaAsSb
In0.53Ga0.47As
InGaAsP graded collector layer
Measurements and analyses referenced in the patent, with their drawing references.
FIG. 1, a generic DHBT structure 10 is shown for discussion purposes. A transistor such as DHBT 10 is typically formed on a substrate 100, and includes a …
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
Band gap of In0.75Ga0.25As0.54P0.46 collector layer | 0.9 eV | In0.75Ga0.25As0.54P0.46 |
DC current gain of fabricated DHBT |
Related documents with shared materials, methods, properties, or citations.
Patent
Atlas literature
Patent
US 8,692,295Patent drawings and their descriptions. Click a drawing to enlarge it.
FIG. 1, a generic DHBT structure 10 is shown for discussion purposes. A transistor such as DHBT 10 is typically formed on a substrate 100, and includes a …
FIG. 2 is a graph depicting Poisson band bending models for the base collector interface for a baseline DHBT and a DHBT formed in accordance with the present …
FIG. 3 is a graph depicting the room temperature photoluminescence spectrum for an MBE-grown Ino.75Gao.25Aso.54Po.46 film deposited on InGaAs, in accordance …
FIG. 4 is a graph depicting the x-ray rocking curve for a DHBT using a lattice matched Ino.75Gao.25Aso.54Po.46 4 collector and a strained base layer, in …
FIG. 5 is a structural block diagram of an integrated opto-electronic device employing a DHBT formed in accordance with the present disclosure.
Claims define the patent's legal scope. Independent claims stand alone; dependent claims (nested) narrow them. Click a claim to expand its dependents.
A bipolar transistor on a substrate, comprising: a collector com p risin g In0Ga025As04 Po.46 having a first conductivity type; a base having a second conductivity type and in contact with the collector; an emitter of the first conductivity type in contact with the base; and electrodes forming separate electrical contacts with each of the collector, base, and emitter, respectively; and wherein the base is formed substantially of InGaAs having a composition having a conduction band energy level higher than Ino.5 3Ga 0. 47As.
The transistor of claim 1, wherein the collector includes a graded layer in contact with the base and varying in composition to minimize a conduction band discontinuity between the base and the collector.
The transistor of claim 1, wherein the collector includes a sub-layer in contact with the substrate and having a higher doping concentration than the rest of the collector.
The transistor of claim 1, further comprising: a sub-collector layer formed substantially of InGaAs of the first conductivity type and in contact with the collector.
The transistor of claim 1, wherein the conduction band energy level of the base at least in the vicinity of the base/collector junction is higher than the conduction band energy level of In o.5 3Ga 0. 47As.
The transistor of claim 1, wherein the Ga mole fraction in the base is above 0.47. U. S. A ppl n. No. 12/567,556 Pa ge 3
The transistor of claim 1, wherein the base is formed substantially of InGaAs or GaAsSb.
The transistor of claim 1, wherein the collector is configured to form a waveguide for light having a 1.5 micron wavelength.
The transistor of claim 1, wherein the collector is configured to form a waveguide for light. previously presented
The transistor of claim 1, wherein the base has a thickness of less than 500 Angstroms.
The transistor of claim 1, wherein: the base comprises In o. 44Ga 0s6As;-and th ltrmpiGa--As-s4-P.
canceled
A bipolar transistor on a substrate, comprising: a collector comprising Ino.75Gao.2sAso5 4 Po.46 having a first conductivity type; a base having a second conductivity type and in contact with the collector; an emitter of the first conductivity type in contact with the base; and electrodes forming separate electrical contacts with each of the collector, base, and emitter, respectively; and wherein the base comprises Ino. 44Ga 0s6 As. U. S. A ppl n. No. 12/567,556 Pa ge 4
The transistor of claim 14, wherein the collector comprises a graded layer in contact with the base and varying in composition to minimize a conduction band discontinuity between the base and the collector.
The transistor of claim 14, wherein the collector is configured to form a waveguide for light having a 1.5 micron wavelength.
The transistor of claim 14, wherein the collector is configured to form a waveguide for light.
The transistor of claim 14, wherein the base further comprises In0. 53Ga o. 47As.
The transistor of claim 14, wherein the base has a thickness of less than 500 Angstroms.
The transistor of claim 14 further comprising: a graded collector between the base and the collector to provide smooth grading in the conduction energy band between the base and the collector.
Embodiments described in the patent, grouped by the materials and process steps they use.
6 materials1 process step
A DHBT structure was grown by MBE with an In0.75Ga0.25As0.54P0.46 quaternary collector (~1500 Å, n:7E₁₆ cm⁻³), a coherently strained In0.44Ga0.56As base (~300 Å, p:3E₁₈ cm⁻³), a 450 Å graded InGaAsP collector layer transitioning between base and collector, and an InGaAs sub-collector. A dry-etch process was used to etch the quaternary collector. DC gain of ~25 was measured; collector breakdown voltage BVceo was as high as 6V for a 2000 Å thick collector; base-emitter turn-on voltage Vbe was 0.6V; reverse breakdown voltage was 2V. PL and x-ray measurements were used to confirm layer composition and lattice matching.
Layer stacks claimed or described, ordered top of device to substrate.
Double Heterojunction Bipolar Transistor (DHBT) — generic InGaAsP collector, high-Ga InGaAs base
Double Heterojunction Bipolar Transistor (DHBT) — In0.75Ga0.25As0.54P0.46 collector, In0.44Ga0.56As base
Materials described outside the worked examples.
GaAsSb
In0.53Ga0.47As
InGaAsP graded collector layer
Measurements and analyses referenced in the patent, with their drawing references.
FIG. 1, a generic DHBT structure 10 is shown for discussion purposes. A transistor such as DHBT 10 is typically formed on a substrate 100, and includes a …
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
Band gap of In0.75Ga0.25As0.54P0.46 collector layer | 0.9 eV | In0.75Ga0.25As0.54P0.46 |
DC current gain of fabricated DHBT |
Related documents with shared materials, methods, properties, or citations.
Patent
Atlas literature
Patent
US 8,692,295Patent drawings and their descriptions. Click a drawing to enlarge it.
FIG. 1, a generic DHBT structure 10 is shown for discussion purposes. A transistor such as DHBT 10 is typically formed on a substrate 100, and includes a …
FIG. 2 is a graph depicting Poisson band bending models for the base collector interface for a baseline DHBT and a DHBT formed in accordance with the present …
FIG. 3 is a graph depicting the room temperature photoluminescence spectrum for an MBE-grown Ino.75Gao.25Aso.54Po.46 film deposited on InGaAs, in accordance …
FIG. 4 is a graph depicting the x-ray rocking curve for a DHBT using a lattice matched Ino.75Gao.25Aso.54Po.46 4 collector and a strained base layer, in …
FIG. 5 is a structural block diagram of an integrated opto-electronic device employing a DHBT formed in accordance with the present disclosure.
Claims define the patent's legal scope. Independent claims stand alone; dependent claims (nested) narrow them. Click a claim to expand its dependents.
A bipolar transistor on a substrate, comprising: a collector com p risin g In0Ga025As04 Po.46 having a first conductivity type; a base having a second conductivity type and in contact with the collector; an emitter of the first conductivity type in contact with the base; and electrodes forming separate electrical contacts with each of the collector, base, and emitter, respectively; and wherein the base is formed substantially of InGaAs having a composition having a conduction band energy level higher than Ino.5 3Ga 0. 47As.
The transistor of claim 1, wherein the collector includes a graded layer in contact with the base and varying in composition to minimize a conduction band discontinuity between the base and the collector.
The transistor of claim 1, wherein the collector includes a sub-layer in contact with the substrate and having a higher doping concentration than the rest of the collector.
The transistor of claim 1, further comprising: a sub-collector layer formed substantially of InGaAs of the first conductivity type and in contact with the collector.
The transistor of claim 1, wherein the conduction band energy level of the base at least in the vicinity of the base/collector junction is higher than the conduction band energy level of In o.5 3Ga 0. 47As.
The transistor of claim 1, wherein the Ga mole fraction in the base is above 0.47. U. S. A ppl n. No. 12/567,556 Pa ge 3
The transistor of claim 1, wherein the base is formed substantially of InGaAs or GaAsSb.
The transistor of claim 1, wherein the collector is configured to form a waveguide for light having a 1.5 micron wavelength.
The transistor of claim 1, wherein the collector is configured to form a waveguide for light. previously presented
The transistor of claim 1, wherein the base has a thickness of less than 500 Angstroms.
The transistor of claim 1, wherein: the base comprises In o. 44Ga 0s6As;-and th ltrmpiGa--As-s4-P.
canceled
A bipolar transistor on a substrate, comprising: a collector comprising Ino.75Gao.2sAso5 4 Po.46 having a first conductivity type; a base having a second conductivity type and in contact with the collector; an emitter of the first conductivity type in contact with the base; and electrodes forming separate electrical contacts with each of the collector, base, and emitter, respectively; and wherein the base comprises Ino. 44Ga 0s6 As. U. S. A ppl n. No. 12/567,556 Pa ge 4
The transistor of claim 14, wherein the collector comprises a graded layer in contact with the base and varying in composition to minimize a conduction band discontinuity between the base and the collector.
The transistor of claim 14, wherein the collector is configured to form a waveguide for light having a 1.5 micron wavelength.
The transistor of claim 14, wherein the collector is configured to form a waveguide for light.
The transistor of claim 14, wherein the base further comprises In0. 53Ga o. 47As.
The transistor of claim 14, wherein the base has a thickness of less than 500 Angstroms.
The transistor of claim 14 further comprising: a graded collector between the base and the collector to provide smooth grading in the conduction energy band between the base and the collector.
Embodiments described in the patent, grouped by the materials and process steps they use.
6 materials1 process step
A DHBT structure was grown by MBE with an In0.75Ga0.25As0.54P0.46 quaternary collector (~1500 Å, n:7E₁₆ cm⁻³), a coherently strained In0.44Ga0.56As base (~300 Å, p:3E₁₈ cm⁻³), a 450 Å graded InGaAsP collector layer transitioning between base and collector, and an InGaAs sub-collector. A dry-etch process was used to etch the quaternary collector. DC gain of ~25 was measured; collector breakdown voltage BVceo was as high as 6V for a 2000 Å thick collector; base-emitter turn-on voltage Vbe was 0.6V; reverse breakdown voltage was 2V. PL and x-ray measurements were used to confirm layer composition and lattice matching.
Layer stacks claimed or described, ordered top of device to substrate.
Double Heterojunction Bipolar Transistor (DHBT) — generic InGaAsP collector, high-Ga InGaAs base
Double Heterojunction Bipolar Transistor (DHBT) — In0.75Ga0.25As0.54P0.46 collector, In0.44Ga0.56As base
Materials described outside the worked examples.
GaAsSb
In0.53Ga0.47As
InGaAsP graded collector layer
Measurements and analyses referenced in the patent, with their drawing references.
FIG. 1, a generic DHBT structure 10 is shown for discussion purposes. A transistor such as DHBT 10 is typically formed on a substrate 100, and includes a …
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
Band gap of In0.75Ga0.25As0.54P0.46 collector layer | 0.9 eV | In0.75Ga0.25As0.54P0.46 |
DC current gain of fabricated DHBT |
Related documents with shared materials, methods, properties, or citations.
DHBT with integrated opto-electronic device
FIG. 3 is a graph depicting the room temperature photoluminescence spectrum for an MBE-grown Ino.75Gao.25Aso.54Po.46 film deposited on InGaAs, in accordance …
| 25 dimensionless (approximate) |
| — |
Collector breakdown voltage BVceo | 6 V | — |
Base-emitter turn-on voltage Vbe | 0.6 V | — |
Reverse breakdown voltage | 2 V | — |
XRD peak from strained In0.53Ga0.47As base layer in x-ray rocking curve | 32.06 degrees | In0.53Ga0.47As |
— | 0.1–0.1 eV | — |
Thickness | ≤ 500 Å | — |
DHBT with integrated opto-electronic device
FIG. 3 is a graph depicting the room temperature photoluminescence spectrum for an MBE-grown Ino.75Gao.25Aso.54Po.46 film deposited on InGaAs, in accordance …
| 25 dimensionless (approximate) |
| — |
Collector breakdown voltage BVceo | 6 V | — |
Base-emitter turn-on voltage Vbe | 0.6 V | — |
Reverse breakdown voltage | 2 V | — |
XRD peak from strained In0.53Ga0.47As base layer in x-ray rocking curve | 32.06 degrees | In0.53Ga0.47As |
— | 0.1–0.1 eV | — |
Thickness | ≤ 500 Å | — |
DHBT with integrated opto-electronic device
FIG. 3 is a graph depicting the room temperature photoluminescence spectrum for an MBE-grown Ino.75Gao.25Aso.54Po.46 film deposited on InGaAs, in accordance …
| 25 dimensionless (approximate) |
| — |
Collector breakdown voltage BVceo | 6 V | — |
Base-emitter turn-on voltage Vbe | 0.6 V | — |
Reverse breakdown voltage | 2 V | — |
XRD peak from strained In0.53Ga0.47As base layer in x-ray rocking curve | 32.06 degrees | In0.53Ga0.47As |
— | 0.1–0.1 eV | — |
Thickness | ≤ 500 Å | — |
DHBT with integrated opto-electronic device
FIG. 3 is a graph depicting the room temperature photoluminescence spectrum for an MBE-grown Ino.75Gao.25Aso.54Po.46 film deposited on InGaAs, in accordance …
| 25 dimensionless (approximate) |
| — |
Collector breakdown voltage BVceo | 6 V | — |
Base-emitter turn-on voltage Vbe | 0.6 V | — |
Reverse breakdown voltage | 2 V | — |
XRD peak from strained In0.53Ga0.47As base layer in x-ray rocking curve | 32.06 degrees | In0.53Ga0.47As |
— | 0.1–0.1 eV | — |
Thickness | ≤ 500 Å | — |