Patent
US 10,269,989WATER-INSENSITIVE GAS SENSOR USING POLYMER-ENCAPSULATED Pt-AlGaN/GaN DIODES
Fan Ren
US
Copyright © 2026 Matter42. All rights reserved.
Patent
Atlas literature
Patent
US 10,269,989Patent drawings and their descriptions. Click a drawing to enlarge it.
Figure 1 shows an optical microscope image of a hydrogen sensor according to an embodiment of the subject invention.
Figure 2(a) shows a cross-sectional view taken along line A-A' in
Figure 3 shows optical microscope images of a hydrogen sensor according to an embodiment o f the subject invention before and after thermal cycle.
Figure 4(a) shows I -V characteristics of an un-encapsulated hydrogen sensor before and after 500 ppm H 2 exposure.
Figure 5(a) shows a time response of an un-encapsulated hydrogen sensor for dry 500 ppm hydrogen exposure.
Figure 6(a) shows a current response with respect to H 2 concentration of an un- encapsulated hydrogen sensor.
Figure 7 shows selective characteristics with respect to H 2 of an encapsulated hydrogen sensor according to an embodiment of the subject invention.
Figure 8 shows a current change with respect to exposure time of an encapsulated hydrogen sensor according to an embodiment of the subject invention.
Figure 9(a) shows a relative current change of an unheated encapsulated hydrogen sensor according to an embodiment of the subject invention.
Figure 10 shows a relative current change wi th respect to water of un-encapsulated and encapsulated hydrogen sensors.
Figure 11(a) shows a response of an un-encapsulated hydrogen sensor.
Claims define the patent's legal scope. Independent claims stand alone; dependent claims (nested) narrow them. Click a claim to expand its dependents.
A hydrogen sensor, comprising: a substrate; an Ohmic metal disposed on the substrate; a nitride layer disposed on the substrate and having a first window exposing the substrate; a Schottky metal placed in the first window and disposed on the substrate; a final metal disposed on the nitride layer and the Schottky metal and having a second window exposing the Schottky metal; and a polymethyl-methacrylate (PMMA) layer encapsulating the second window.
The hydrogen sensor according to claim 1, wherein the PMMA layer covers a part of the Ohmic metal and a part of the final metal.
1 7. The Schottk y diode according to claim 1 6, wherein the polymer encapsulant covers the Ohmic metal, the nitride layer, the Schottk y metal, the final metal, and the substrate.
A Schottky diode, comprising: a substrate; an Ohmic metal disposed on an Ohmic contact area of the substrate; a nitride layer disposed on the substrate and having a window exposing a S c hottky contact area of the substrate; a Scho ttky metal disposed on the Schot t ky contact area of the substrate; a final metal connected to the Schottk y metal; and a polymer encapsulant disposed directly on the Sc h ottky metal.
The Schottk y diode according to claim 14, wherein the Schottky metal is platinum.
The Schottky diode according to 17, wherein the polymer encapsulant comprises at least one of polymethyl-metha c rylate (PMMA), polyimide, poly c arbonate, and benzocyclobutene (BCB).
A method for manufacturing a hydrogen sensor, the method comprising: providing a substrate; forming an Ohmic metal on an Ohmic contact area of the substrate; depositing a nitride layer on the substrate and the Ohmic metal; forming a first window exposing a Schottky contact area of the substrate by removing the nitride layer on the substrate; forming a Schottky metal on the Schottky contact area of the substrate; forming a final metal on the Schot t ky metal; and forming an encapsulating layer encapsulating the Schottky metal.
The method according to claim 19, wherein the encapsulating layer is in direct physical contact with the Schottky metal.
Embodiments described in the patent, grouped by the materials and process steps they use.
4 materials
Hydrogen sensors including Pt-AlGaN/GaN Schottky diodes with PMMA encapsulation were fabricated and tested. Thermal stability was confirmed by cycling devices 50 times between 25-100°C. I-V characteristics, time responses, concentration-dependent current responses, gas selectivity (CH4, CO, NO2, CO2, O₂), and humidity immunity were characterized. PMMA encapsulation eliminated the sensitivity decrease caused by water vapor while retaining the same absolute detection sensitivity (~2.8×10⁵% at low forward bias). The sensor responded to hydrogen concentrations as low as 100 ppm. PMMA-encapsulated sensors showed complete selectivity to hydrogen over other gases.
Layer stacks claimed or described, ordered top of device to substrate.
hydrogen sensor (Schottky diode-based)
Materials described outside the worked examples.
Ohmic metal
nitride layer
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
percentage current change at 1.3V forward bias upon exposure to 500 ppm H2 (unheated and thermally cycled encapsulated diodes) | 120000 % | polymethyl-methacrylate (PMMA)PtGaN |
Related documents with shared materials, methods, properties, or citations.
Patent
Atlas literature
Patent
US 10,269,989Patent drawings and their descriptions. Click a drawing to enlarge it.
Figure 1 shows an optical microscope image of a hydrogen sensor according to an embodiment of the subject invention.
Figure 2(a) shows a cross-sectional view taken along line A-A' in
Figure 3 shows optical microscope images of a hydrogen sensor according to an embodiment o f the subject invention before and after thermal cycle.
Figure 4(a) shows I -V characteristics of an un-encapsulated hydrogen sensor before and after 500 ppm H 2 exposure.
Figure 5(a) shows a time response of an un-encapsulated hydrogen sensor for dry 500 ppm hydrogen exposure.
Figure 6(a) shows a current response with respect to H 2 concentration of an un- encapsulated hydrogen sensor.
Figure 7 shows selective characteristics with respect to H 2 of an encapsulated hydrogen sensor according to an embodiment of the subject invention.
Figure 8 shows a current change with respect to exposure time of an encapsulated hydrogen sensor according to an embodiment of the subject invention.
Figure 9(a) shows a relative current change of an unheated encapsulated hydrogen sensor according to an embodiment of the subject invention.
Figure 10 shows a relative current change wi th respect to water of un-encapsulated and encapsulated hydrogen sensors.
Figure 11(a) shows a response of an un-encapsulated hydrogen sensor.
Claims define the patent's legal scope. Independent claims stand alone; dependent claims (nested) narrow them. Click a claim to expand its dependents.
A hydrogen sensor, comprising: a substrate; an Ohmic metal disposed on the substrate; a nitride layer disposed on the substrate and having a first window exposing the substrate; a Schottky metal placed in the first window and disposed on the substrate; a final metal disposed on the nitride layer and the Schottky metal and having a second window exposing the Schottky metal; and a polymethyl-methacrylate (PMMA) layer encapsulating the second window.
The hydrogen sensor according to claim 1, wherein the PMMA layer covers a part of the Ohmic metal and a part of the final metal.
1 7. The Schottk y diode according to claim 1 6, wherein the polymer encapsulant covers the Ohmic metal, the nitride layer, the Schottk y metal, the final metal, and the substrate.
A Schottky diode, comprising: a substrate; an Ohmic metal disposed on an Ohmic contact area of the substrate; a nitride layer disposed on the substrate and having a window exposing a S c hottky contact area of the substrate; a Scho ttky metal disposed on the Schot t ky contact area of the substrate; a final metal connected to the Schottk y metal; and a polymer encapsulant disposed directly on the Sc h ottky metal.
The Schottk y diode according to claim 14, wherein the Schottky metal is platinum.
The Schottky diode according to 17, wherein the polymer encapsulant comprises at least one of polymethyl-metha c rylate (PMMA), polyimide, poly c arbonate, and benzocyclobutene (BCB).
A method for manufacturing a hydrogen sensor, the method comprising: providing a substrate; forming an Ohmic metal on an Ohmic contact area of the substrate; depositing a nitride layer on the substrate and the Ohmic metal; forming a first window exposing a Schottky contact area of the substrate by removing the nitride layer on the substrate; forming a Schottky metal on the Schottky contact area of the substrate; forming a final metal on the Schot t ky metal; and forming an encapsulating layer encapsulating the Schottky metal.
The method according to claim 19, wherein the encapsulating layer is in direct physical contact with the Schottky metal.
Embodiments described in the patent, grouped by the materials and process steps they use.
4 materials
Hydrogen sensors including Pt-AlGaN/GaN Schottky diodes with PMMA encapsulation were fabricated and tested. Thermal stability was confirmed by cycling devices 50 times between 25-100°C. I-V characteristics, time responses, concentration-dependent current responses, gas selectivity (CH4, CO, NO2, CO2, O₂), and humidity immunity were characterized. PMMA encapsulation eliminated the sensitivity decrease caused by water vapor while retaining the same absolute detection sensitivity (~2.8×10⁵% at low forward bias). The sensor responded to hydrogen concentrations as low as 100 ppm. PMMA-encapsulated sensors showed complete selectivity to hydrogen over other gases.
Layer stacks claimed or described, ordered top of device to substrate.
hydrogen sensor (Schottky diode-based)
Materials described outside the worked examples.
Ohmic metal
nitride layer
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
percentage current change at 1.3V forward bias upon exposure to 500 ppm H2 (unheated and thermally cycled encapsulated diodes) | 120000 % | polymethyl-methacrylate (PMMA)PtGaN |
Related documents with shared materials, methods, properties, or citations.
Patent
Atlas literature
Patent
US 10,269,989Patent drawings and their descriptions. Click a drawing to enlarge it.
Figure 1 shows an optical microscope image of a hydrogen sensor according to an embodiment of the subject invention.
Figure 2(a) shows a cross-sectional view taken along line A-A' in
Figure 3 shows optical microscope images of a hydrogen sensor according to an embodiment o f the subject invention before and after thermal cycle.
Figure 4(a) shows I -V characteristics of an un-encapsulated hydrogen sensor before and after 500 ppm H 2 exposure.
Figure 5(a) shows a time response of an un-encapsulated hydrogen sensor for dry 500 ppm hydrogen exposure.
Figure 6(a) shows a current response with respect to H 2 concentration of an un- encapsulated hydrogen sensor.
Figure 7 shows selective characteristics with respect to H 2 of an encapsulated hydrogen sensor according to an embodiment of the subject invention.
Figure 8 shows a current change with respect to exposure time of an encapsulated hydrogen sensor according to an embodiment of the subject invention.
Figure 9(a) shows a relative current change of an unheated encapsulated hydrogen sensor according to an embodiment of the subject invention.
Figure 10 shows a relative current change wi th respect to water of un-encapsulated and encapsulated hydrogen sensors.
Figure 11(a) shows a response of an un-encapsulated hydrogen sensor.
Claims define the patent's legal scope. Independent claims stand alone; dependent claims (nested) narrow them. Click a claim to expand its dependents.
A hydrogen sensor, comprising: a substrate; an Ohmic metal disposed on the substrate; a nitride layer disposed on the substrate and having a first window exposing the substrate; a Schottky metal placed in the first window and disposed on the substrate; a final metal disposed on the nitride layer and the Schottky metal and having a second window exposing the Schottky metal; and a polymethyl-methacrylate (PMMA) layer encapsulating the second window.
The hydrogen sensor according to claim 1, wherein the PMMA layer covers a part of the Ohmic metal and a part of the final metal.
1 7. The Schottk y diode according to claim 1 6, wherein the polymer encapsulant covers the Ohmic metal, the nitride layer, the Schottk y metal, the final metal, and the substrate.
A Schottky diode, comprising: a substrate; an Ohmic metal disposed on an Ohmic contact area of the substrate; a nitride layer disposed on the substrate and having a window exposing a S c hottky contact area of the substrate; a Scho ttky metal disposed on the Schot t ky contact area of the substrate; a final metal connected to the Schottk y metal; and a polymer encapsulant disposed directly on the Sc h ottky metal.
The Schottk y diode according to claim 14, wherein the Schottky metal is platinum.
The Schottky diode according to 17, wherein the polymer encapsulant comprises at least one of polymethyl-metha c rylate (PMMA), polyimide, poly c arbonate, and benzocyclobutene (BCB).
A method for manufacturing a hydrogen sensor, the method comprising: providing a substrate; forming an Ohmic metal on an Ohmic contact area of the substrate; depositing a nitride layer on the substrate and the Ohmic metal; forming a first window exposing a Schottky contact area of the substrate by removing the nitride layer on the substrate; forming a Schottky metal on the Schottky contact area of the substrate; forming a final metal on the Schot t ky metal; and forming an encapsulating layer encapsulating the Schottky metal.
The method according to claim 19, wherein the encapsulating layer is in direct physical contact with the Schottky metal.
Embodiments described in the patent, grouped by the materials and process steps they use.
4 materials
Hydrogen sensors including Pt-AlGaN/GaN Schottky diodes with PMMA encapsulation were fabricated and tested. Thermal stability was confirmed by cycling devices 50 times between 25-100°C. I-V characteristics, time responses, concentration-dependent current responses, gas selectivity (CH4, CO, NO2, CO2, O₂), and humidity immunity were characterized. PMMA encapsulation eliminated the sensitivity decrease caused by water vapor while retaining the same absolute detection sensitivity (~2.8×10⁵% at low forward bias). The sensor responded to hydrogen concentrations as low as 100 ppm. PMMA-encapsulated sensors showed complete selectivity to hydrogen over other gases.
Layer stacks claimed or described, ordered top of device to substrate.
hydrogen sensor (Schottky diode-based)
Materials described outside the worked examples.
Ohmic metal
nitride layer
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
percentage current change at 1.3V forward bias upon exposure to 500 ppm H2 (unheated and thermally cycled encapsulated diodes) | 120000 % | polymethyl-methacrylate (PMMA)PtGaN |
Related documents with shared materials, methods, properties, or citations.
Patent
Atlas literature
Patent
US 10,269,989Patent drawings and their descriptions. Click a drawing to enlarge it.
Figure 1 shows an optical microscope image of a hydrogen sensor according to an embodiment of the subject invention.
Figure 2(a) shows a cross-sectional view taken along line A-A' in
Figure 3 shows optical microscope images of a hydrogen sensor according to an embodiment o f the subject invention before and after thermal cycle.
Figure 4(a) shows I -V characteristics of an un-encapsulated hydrogen sensor before and after 500 ppm H 2 exposure.
Figure 5(a) shows a time response of an un-encapsulated hydrogen sensor for dry 500 ppm hydrogen exposure.
Figure 6(a) shows a current response with respect to H 2 concentration of an un- encapsulated hydrogen sensor.
Figure 7 shows selective characteristics with respect to H 2 of an encapsulated hydrogen sensor according to an embodiment of the subject invention.
Figure 8 shows a current change with respect to exposure time of an encapsulated hydrogen sensor according to an embodiment of the subject invention.
Figure 9(a) shows a relative current change of an unheated encapsulated hydrogen sensor according to an embodiment of the subject invention.
Figure 10 shows a relative current change wi th respect to water of un-encapsulated and encapsulated hydrogen sensors.
Figure 11(a) shows a response of an un-encapsulated hydrogen sensor.
Claims define the patent's legal scope. Independent claims stand alone; dependent claims (nested) narrow them. Click a claim to expand its dependents.
A hydrogen sensor, comprising: a substrate; an Ohmic metal disposed on the substrate; a nitride layer disposed on the substrate and having a first window exposing the substrate; a Schottky metal placed in the first window and disposed on the substrate; a final metal disposed on the nitride layer and the Schottky metal and having a second window exposing the Schottky metal; and a polymethyl-methacrylate (PMMA) layer encapsulating the second window.
The hydrogen sensor according to claim 1, wherein the PMMA layer covers a part of the Ohmic metal and a part of the final metal.
1 7. The Schottk y diode according to claim 1 6, wherein the polymer encapsulant covers the Ohmic metal, the nitride layer, the Schottk y metal, the final metal, and the substrate.
A Schottky diode, comprising: a substrate; an Ohmic metal disposed on an Ohmic contact area of the substrate; a nitride layer disposed on the substrate and having a window exposing a S c hottky contact area of the substrate; a Scho ttky metal disposed on the Schot t ky contact area of the substrate; a final metal connected to the Schottk y metal; and a polymer encapsulant disposed directly on the Sc h ottky metal.
The Schottk y diode according to claim 14, wherein the Schottky metal is platinum.
The Schottky diode according to 17, wherein the polymer encapsulant comprises at least one of polymethyl-metha c rylate (PMMA), polyimide, poly c arbonate, and benzocyclobutene (BCB).
A method for manufacturing a hydrogen sensor, the method comprising: providing a substrate; forming an Ohmic metal on an Ohmic contact area of the substrate; depositing a nitride layer on the substrate and the Ohmic metal; forming a first window exposing a Schottky contact area of the substrate by removing the nitride layer on the substrate; forming a Schottky metal on the Schottky contact area of the substrate; forming a final metal on the Schot t ky metal; and forming an encapsulating layer encapsulating the Schottky metal.
The method according to claim 19, wherein the encapsulating layer is in direct physical contact with the Schottky metal.
Embodiments described in the patent, grouped by the materials and process steps they use.
4 materials
Hydrogen sensors including Pt-AlGaN/GaN Schottky diodes with PMMA encapsulation were fabricated and tested. Thermal stability was confirmed by cycling devices 50 times between 25-100°C. I-V characteristics, time responses, concentration-dependent current responses, gas selectivity (CH4, CO, NO2, CO2, O₂), and humidity immunity were characterized. PMMA encapsulation eliminated the sensitivity decrease caused by water vapor while retaining the same absolute detection sensitivity (~2.8×10⁵% at low forward bias). The sensor responded to hydrogen concentrations as low as 100 ppm. PMMA-encapsulated sensors showed complete selectivity to hydrogen over other gases.
Layer stacks claimed or described, ordered top of device to substrate.
hydrogen sensor (Schottky diode-based)
Materials described outside the worked examples.
Ohmic metal
nitride layer
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
percentage current change at 1.3V forward bias upon exposure to 500 ppm H2 (unheated and thermally cycled encapsulated diodes) | 120000 % | polymethyl-methacrylate (PMMA)PtGaN |
Related documents with shared materials, methods, properties, or citations.
Schottky diode
Schottky metal
final metal
sapphire
Al₂O₃
titanium
Ti
aluminum
Al
nickel
Ni
gold
Au
silicon carbide
SiC
silicon
Si
polymer encapsulant
polyimide
polycarbonate
benzocyclobutene (BCB)
encapsulating layer
absolute detection sensitivity at low forward bias (PMMA encapsulated, dry or wet H2) | 280000 % | polymethyl-methacrylate (PMMA)PtGaNAlxGa₁-xN |
minimum detectable H2 concentration | 100 ppm | polymethyl-methacrylate (PMMA)PtGaNAlxGa₁-xN |
Temperature | 25–100 °C | — |
Schottky diode
Schottky metal
final metal
sapphire
Al₂O₃
titanium
Ti
aluminum
Al
nickel
Ni
gold
Au
silicon carbide
SiC
silicon
Si
polymer encapsulant
polyimide
polycarbonate
benzocyclobutene (BCB)
encapsulating layer
absolute detection sensitivity at low forward bias (PMMA encapsulated, dry or wet H2) | 280000 % | polymethyl-methacrylate (PMMA)PtGaNAlxGa₁-xN |
minimum detectable H2 concentration | 100 ppm | polymethyl-methacrylate (PMMA)PtGaNAlxGa₁-xN |
Temperature | 25–100 °C | — |
Schottky diode
Schottky metal
final metal
sapphire
Al₂O₃
titanium
Ti
aluminum
Al
nickel
Ni
gold
Au
silicon carbide
SiC
silicon
Si
polymer encapsulant
polyimide
polycarbonate
benzocyclobutene (BCB)
encapsulating layer
absolute detection sensitivity at low forward bias (PMMA encapsulated, dry or wet H2) | 280000 % | polymethyl-methacrylate (PMMA)PtGaNAlxGa₁-xN |
minimum detectable H2 concentration | 100 ppm | polymethyl-methacrylate (PMMA)PtGaNAlxGa₁-xN |
Temperature | 25–100 °C | — |
Schottky diode
Schottky metal
final metal
sapphire
Al₂O₃
titanium
Ti
aluminum
Al
nickel
Ni
gold
Au
silicon carbide
SiC
silicon
Si
polymer encapsulant
polyimide
polycarbonate
benzocyclobutene (BCB)
encapsulating layer
absolute detection sensitivity at low forward bias (PMMA encapsulated, dry or wet H2) | 280000 % | polymethyl-methacrylate (PMMA)PtGaNAlxGa₁-xN |
minimum detectable H2 concentration | 100 ppm | polymethyl-methacrylate (PMMA)PtGaNAlxGa₁-xN |
Temperature | 25–100 °C | — |