WO2012074367A1 - Resistive ion sensing device - Google Patents
Resistive ion sensing device Download PDFInfo
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- WO2012074367A1 WO2012074367A1 PCT/MY2011/000151 MY2011000151W WO2012074367A1 WO 2012074367 A1 WO2012074367 A1 WO 2012074367A1 MY 2011000151 W MY2011000151 W MY 2011000151W WO 2012074367 A1 WO2012074367 A1 WO 2012074367A1
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- G—PHYSICS
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/12—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid, for detecting components in the fluid
- G01N27/125—Composition of the body, e.g. the composition of its sensitive layer
- G01N27/127—Composition of the body, e.g. the composition of its sensitive layer comprising nanoparticles
Definitions
- the present invention relates to a device for sensing ions based on a change in electrical resistance.
- This invention relates to a sensor device based on a change in electrical resistance comprising: a resistor structure having two ends; a plurality of nanostructures attached to at least a portion of said resistor structure; a pair of contact pads, each contact pad located at each said end of the resistor structure; a substrate supporting each said end of the resistor structure; and an insulating layer sandwiched between said substrate and each said end of the resistor structure.
- the resistor structure between each said contact pad comprises either a long wire shaped in a serpentine fashion to cover a larger area or a plurality of wires running parallel to each other.
- nanostructures are either nanotubes or nanowires selected from a group consisting and not limited to carbon nanotubes, silicon nanowires, tungsten nanowires, tungsten oxide nanowires, zinc oxide nanowires, indium oxide nanowires, tin oxide nanowires, gold nanowires or a combination thereof.
- the nanostructures may be either uni-directional or multidirectional.
- the insulating layers are any or a combination of: silicon dioxide or silicon nitride deposited by physical or chemical vapour deposition; or silicon dioxide grown by a thermal oxidation method;
- etching the said back side insulating layer done using either Tetrafluoromethane (CF 4 ) and Trifluoromethane (CHF 3 ) plasma or in a hydrofluoric acid (HF) based chemical solution; c) depositing a first metal catalyst layer on the said front side insulating layer by physical or chemical vapour deposition (PVD or CVD) and made from any or a combination of: gold (Au), cobalt (Co), iron (Fe), nickel (Ni), indium (In) and copper (Cu);
- a second metal catalyst layer on top of the said conductive layer by physical or chemical vapour deposition (PVD or CVD) and made from any or a combination of: gold (Au), cobalt (Co), iron (Fe), nickel (Ni), indium (In) and copper (Cu);
- CVD chemical vapour deposition
- MOCVD metalorganic chemical vapour deposition
- PECVD plasma enhanced chemical vapour deposition
- HWCVD hot wire chemical vapour deposition
- ALD atomic layer deposition
- electrochemical deposition solution chemical deposition or combinations thereof.
- Figures 5 (c) shows a cross sectional view of a first embodiment of this invention where the nanostructures (20) are ordered in a vertical uni-directional array (203).
- the said backside masking material (706) is selected from a group consisting and not limited to polymers, silicon, chrome (Cr), molybdenum (Mo), gold (Au) and silver (Ag).
- the said substrate (40) is done using hydrofluoric acid (HF) or combination with inductively couple plasma reactive ion etching (ICP-RIE) method with octafluorocyclobutane (C 4 F 8 ) plasma.
- Figure 9 shows a process flow in a fabrication process using a glass substrate and a multiple deposition and multiple etching step comprising the steps of:
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Abstract
A sensor device and method of fabrication based on a change in electrical resistance comprising: a resistor structure having two ends; a plurality of 5 nanostructures attached to at least a portion of said resistor structure; a pair of contact pads, each contact pad located at each said end of the resistor structure; a substrate supporting each said end of the resistor structure; and an insulating layer sandwiched between said substrate and each said end of the resistor structure. The resistor structure between each said contact pad comprises either a long wire shaped in a serpentine fashion to cover a larger area or a plurality of wires running parallel to each other. In operation, an electrical current is maintained along the said resistor structure and the said nanostructures upon detecting receptive ions, changes the resistance of the said resistor structure, said change in resistance measurable by an external measuring means.
Description
RESISTIVE ION SENSING DEVICE
FIELD OF INVENTION The present invention relates to a device for sensing ions based on a change in electrical resistance.
BACKGROUND OF INVENTION Chemical gas detection has many applications in agriculture, environmental monitoring, biomedical and industrial processes. With the emergence of nanotechnology, new sensing materials have been developed, thus allowing passive type devices such as resistors to be used as a chemical sensing platform. Chemical sensors are attracting tremendous interest due to their widespread applications in industry, environmental monitoring, space exploration, biomedicine, and pharmaceutics. Gas sensors with high sensitivity and selectivity are required for leakage detections of explosive gases such as hydrogen, and for real-time detections of toxic or pathogenic gases in industries. There is also a strong demand for the ability to monitor and control our ambient environment, especially with the increasing concern of the globe warming. Micro sensors fabricated by MEMS technology have the advantages of small size, high performance, low cost and easy mass-production. With the emergence of nanotechnology, new sensing materials have been developed, thus allowing passive type devices such as micro- resistors to be used as a chemical sensing platform. However, at present such devices are more 2-dimensional with nanostructures and nano-materials incorporated only on the device surface utilising less than 50% of the total device area. Hence there is a limited area for ion detection resulting in lower or limited device sensitivity and performance. What is desirable is a device that utilises a larger portion of the device surface area.
SUMMARY OF INVENTION
The present invention aims at providing a device that fully utilises its surface area by forming receptive nanostructures at all sides of a resistive structure.
This invention relates to a sensor device based on a change in electrical resistance comprising: a resistor structure having two ends; a plurality of nanostructures attached to at least a portion of said resistor structure; a pair of contact pads, each contact pad located at each said end of the resistor structure; a substrate supporting each said end of the resistor structure; and an insulating layer sandwiched between said substrate and each said end of the resistor structure. The resistor structure between each said contact pad comprises either a long wire shaped in a serpentine fashion to cover a larger area or a plurality of wires running parallel to each other. In operation, an electrical current is maintained along the said resistor structure and the said nanostructures upon detecting receptive ions, changes the resistance of the said resistor structure, said change in resistance measurable by an external measuring means. The nanostructures are either nanotubes or nanowires selected from a group consisting and not limited to carbon nanotubes, silicon nanowires, tungsten nanowires, tungsten oxide nanowires, zinc oxide nanowires, indium oxide nanowires, tin oxide nanowires, gold nanowires or a combination thereof. The nanostructures may be either uni-directional or multidirectional.
This invention also relates to a method of fabricating a sensor device comprising the steps of:
a) depositing insulating layers onto a front and a back side of a silicon substrate, the insulating layers are any or a combination of: silicon dioxide or silicon nitride deposited by physical or chemical vapour deposition; or silicon dioxide grown by a thermal oxidation method;
b) etching the said back side insulating layer done using either Tetrafluoromethane (CF4) and Trifluoromethane (CHF3) plasma or in a hydrofluoric acid (HF) based chemical solution;
c) depositing a first metal catalyst layer on the said front side insulating layer by physical or chemical vapour deposition (PVD or CVD) and made from any or a combination of: gold (Au), cobalt (Co), iron (Fe), nickel (Ni), indium (In) and copper (Cu);
d) depositing a conductive layer on the said first metal catalyst layer by PVD or CVD and made from any or a combination of: gold (Au), platinum (Pt), nickel (Ni), tungsten (W), cobalt (Co) and copper (Cu);
e) depositing a second metal catalyst layer on top of the said conductive layer by physical or chemical vapour deposition (PVD or CVD) and made from any or a combination of: gold (Au), cobalt (Co), iron (Fe), nickel (Ni), indium (In) and copper (Cu);
f) etching the said first metal catalyst layer, conductive layer and second metal catalyst layer simultaneously to form resistor and contact pad areas with Argon (Ar) plasma or in a wet chemical solution using an inductively coupled plasma reactive ion etching (ICP-RIE) method with sulphur hexafluoride (SF6) based plasma, or with a wet chemical etchant of potassium hydroxide (KOH) or Tetramethylammonium Hydroxide (TMAH); g) removing the said second metal catalyst layer from the said contact pad areas using buffered hydrofluoric acid (HF);
h) etching the said silicon substrate from the bottom to form an opening beneath the said front side insulating layer;
i) removing the said front side insulating layer from a resistor region, said resistor region located between the said contact pads; and
j) growing of nanostructures at the said resistor region from the exposed metal catalyst areas using a method selected from the group consisting of chemical vapour deposition (CVD), metalorganic chemical vapour deposition (MOCVD), plasma enhanced chemical vapour deposition (PECVD), hot wire chemical vapour deposition (HWCVD), atomic layer deposition (ALD), electrochemical deposition, solution chemical deposition or combinations thereof.
This invention also relates to a method of fabricating a sensor device comprising the steps of:
a) depositing insulating layers onto a front and a back side of a silicon substrate;
b) etching the said back side insulating layer;
c) depositing and etching a first metal catalyst layer on the said front side insulating layer;
d) depositing and etching a conductive layer on the said first metal catalyst layer;
e) depositing and etching a second metal catalyst layer on top of the said conductive layer;
f) etching the said silicon substrate from the bottom to form an opening beneath the said front side insulating layer;
g) removing the said front side insulating layer from a resistor region, said resistor region located between the said contact pads; and
h) growing of nanostructures at the said resistor region from the exposed metal catalyst areas.
This invention also relates to method of fabricating a sensor device comprising the steps of:
a) depositing a first metal catalyst layer on a substrate;
b) depositing a conductive layer on the said first metal catalyst layer;
c) depositing a second metal catalyst layer on top of the said conductive layer; d) etching the said first metal catalyst layer, conductive layer and second metal catalyst layer simultaneously to form resistor and contact pad areas;
e) removing the said second metal catalyst layer from the said contact pad areas;
f) depositing and etching a backside masking material to be use as a mask during glass etching;
g) etching the said substrate from the bottom to form an opening beneath a resistor region, said resistor region located between the said contact pads;
h) growing of nanostructures at the said resistor region from the exposed metal catalyst areas.
The metal catalysts are deposited by physical or chemical vapour deposition (PVD or CVD) and made from any or a combination of: gold (Au), cobalt (Co), iron (Fe), nickel (Ni), indium (In) and copper (Cu). The conductive layer (704) is deposited by PVD or CVD and made from any or a combination of: gold (Au), platinum (Pt), nickel (Ni), tungsten (W), cobalt (Co) and copper (Cu). The said etching of the said first metal catalyst layer (703), conductive layer (704) and second metal catalyst layer simultaneously is done with Argon (Ar) plasma or in a wet chemical solution. The said backside masking material is selected from a group consisting and not limited to polymers, silicon, chrome (Cr), molybdenum (Mo), gold (Au) and silver (Ag). The said substrate is done using hydrofluoric acid (HF) or combination with inductively couple plasma reactive ion etching (ICP-RIE) method with octafluorocyclobutane (C4F8) plasma. The said growing of nanostructures at the said resistor region is done using a method selected from the group consisting of chemical vapour deposition (CVD), metalorganic chemical vapour deposition (MOCVD), plasma enhanced chemical vapour deposition (PECVD), hot wire chemical vapour deposition (HWCVD), atomic layer deposition (ALD), electrochemical deposition, solution chemical deposition or combinations thereof.
This invention also relates to method of fabricating a sensor device comprising the steps of:
a) depositing and etching a first metal catalyst layer on a glass substrate; b) depositing and etching a conductive layer on the said first metal catalyst layer;
c) depositing and etching a second metal catalyst layer on top of the said conductive layer;
d) depositing and etching a backside masking material to be used as a mask during glass etching;
e) etching the glass substrate from the bottom to form an opening beneath a resistor region, said resistor region located between the said contact pads; and
f) growing of nanostructures at the said resistor region from the exposed metal catalyst areas.
The metal catalysts are deposited by physical or chemical vapour deposition (PVD or CVD) and made from any or a combination of: gold (Au), cobalt (Co), iron (Fe), nickel (Ni), indium (In) and copper (Cu). The said conductive layer is deposited by PVD or CVD and made from any or a combination of: gold (Au), platinum (Pt), nickel (Ni), tungsten (W), cobalt (Co) and copper (Cu). The said etching of the said first metal catalyst layer, conductive layer and second metal catalyst layer simultaneously is done with Argon (Ar) plasma or in a wet chemical solution. The said backside masking material is selected from a group consisting and not limited to polymers, silicon, chrome (Cr), molybdenum (Mo), gold (Au) and silver (Ag). The said etching of the said substrate (40) is done using hydrofluoric acid (HF) or combination with inductively couple plasma reactive ion etching (ICP-RIE) method with octafluorocyclobutane (C4F8) plasma. The said growing of nanostructures at the said resistor region is done using a method selected from the group consisting of chemical vapour deposition (CVD), metalorganic chemical vapour deposition (MOCVD), plasma enhanced chemical vapour deposition (PECVD), hot wire chemical vapour deposition (HWCVD), atomic layer deposition (ALD), electrochemical deposition, solution chemical deposition or combinations thereof. These and other objects of the present invention will become more readily apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating the preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
BRIEF DESCRIPTION OF DRAWINGS
Figure 1 shows a view of a sensing device in an embodiment of this invention. Figure 2a shows a plan view of an embodiment of this invention. Figure 2b shows a plan view of an embodiment of this invention. Figure 3 shows a process flow of an embodiment of this invention.
Figure 4 shows a process flow of an embodiment of this invention.
Figure 5a shows a cross sectional view of an embodiment of this invention. Figure 5b shows a cross sectional view of an embodiment of this invention.
Figure 5 shows a cross sectional view of an embodiment of this invention.
Figure 6 (a) through (j) show stages in the fabrication process of an embodiment of this invention.
Figures 7 (a) through (h) show stages in the fabrication process of an embodiment of this invention. Figures 8 (a) through (h) show stages in the fabrication process of an embodiment of this invention.
Figures 9 (a) through (f) show stages in the fabrication process of an embodiment of this invention.
DETAILED DESCRIPTION OF INVENTION
It should be noted that the following detailed description is directed to a sensing device that fully utilises its fringing field effect by incorporating a second sensing membrane on the opposite side of the interdigitated electrode to the side with the first sensing membrane and the fabrication method thereof and is not limited to any particular size or configuration but in fact a multitude of sizes and configurations within the general scope of the following description. Referring to Figure 1 , there is shown a sensor device based on a change in electrical resistance comprising: a resistor structure (10) having two ends; a plurality of nanostructures (20) attached to at least a portion of said resistor structure (10); a pair of contact pads (50, 52), each contact pad located at each said end of the resistor structure (10); a substrate (40) supporting each said end of the resistor structure (10); and an insulating layer (30, 32) sandwiched between said substrate (40) and each said end of the resistor structure (10).
Referring to Figure 2a, there is shown that a resistor region of the said resistor structure (10) between each said contact pad (50, 52) comprising a long wire shaped in a serpentine fashion (12) to cover a larger area.
Figure 2b shows another embodiment whereby a resistor region of the said resistor structure (10) between each said contact pad (50, 52) comprises or a plurality of wires (14) running parallel to each other.
In operation, an electrical current is maintained along the said resistor structure (10) and the said nanostructures (20) upon detecting receptive ions, changes the resistance of the said resistor structure, said change in resistance measurable by an external measuring means. The nanostructures (20) are either nanotubes or nanowires selected from a group consisting and not limited to carbon nanotubes,
silicon nanowires, tungsten nanowires, tungsten oxide nanowires, zinc oxide nanowires, indium oxide nanowires, tin oxide nanowires, gold nanowires or a combination thereof. The nanostructures may be either uni-directional or multidirectional.
Figure 3 shows a process flow of a multiple deposition and single etching step in an embodiment of this invention.
Figure 4 shows a process flow of a multiple deposition and multiple etching step in an embodiment of this invention.
Figures 5 (a) shows a cross sectional view of a first embodiment of this invention where the nanostructures (20) are ordered in a vertical uni-directional array (201 ). Figures 5 (b) shows a cross sectional view of a first embodiment of this invention where the nanostructures (20) are ordered in a vertical uni-directional array (202).
Figures 5 (c) shows a cross sectional view of a first embodiment of this invention where the nanostructures (20) are ordered in a vertical uni-directional array (203).
Figure 6 shows a process flow in a fabrication process using a silicon substrate and a multiple deposition and single etching step comprising the steps of:
a) depositing insulating layers onto a front (700) and a back (701 ) side of a silicon substrate (40), the insulating layers (700, 701 ) are any or a combination of: silicon dioxide or silicon nitride deposited by physical or chemical vapour deposition; or silicon dioxide grown by a thermal oxidation method;
b) etching the said back side insulating layer (701 ) done using either Tetrafluoromethane (CF4) and Trifluoromethane (CHF3) plasma or in a hydrofluoric acid (HF) based chemical solution;
c) depositing a first metal catalyst layer (703) on the said front side insulating layer (700) by physical or chemical vapour deposition (PVD or CVD) and
made from any or a combination of: gold (Au), cobalt (Co), iron (Fe), nickel (Ni), indium (In) and copper (Cu);
d) depositing a conductive layer (704) on the said first metal catalyst layer (703) by PVD or CVD and made from any or a combination of: gold (Au), platinum (Pt), nickel (Ni), tungsten (W), cobalt (Co) and copper (Cu);
e) depositing a second metal catalyst layer (705) on top of the said conductive layer (704) by physical or chemical vapour deposition (PVD or CVD) and made from any or a combination of: gold (Au), cobalt (Co), iron (Fe), nickel (Ni), indium (In) and copper (Cu);
f) etching the said first metal catalyst layer (703), conductive layer (704) and second metal catalyst layer (705) simultaneously to form resistor and contact pad areas (50, 52) with Argon (Ar) plasma or in a wet chemical solution using an inductively coupled plasma reactive ion etching (ICP-RIE) method with sulphur hexafluoride (SF6) based plasma, or with a wet chemical etchant of potassium hydroxide (KOH) or Tetramethylammonium Hydroxide (TMAH);
g) removing the said second metal catalyst layer (705) from the said contact pad areas (50, 52) using buffered hydrofluoric acid (HF);
h) etching the said silicon substrate (40) from the bottom to form an opening beneath the said front side insulating layer (700);
i) removing the said front side insulating layer (700) from a resistor region, said resistor region located between the said contact pads (50, 52); and j) growing of nanostructures at the said resistor region from the exposed metal catalyst (703, 705) areas using a method selected from the group consisting of chemical vapour deposition (CVD), metalorganic chemical vapour deposition (MOCVD), plasma enhanced chemical vapour deposition (PECVD), hot wire chemical vapour deposition (HWCVD), atomic layer deposition (ALD), electrochemical deposition, solution chemical deposition or combinations thereof.
Figure 7 shows a process flow in a fabrication process using a silicon substrate and a multiple deposition and multiple etching step comprising the steps of:
a) depositing insulating layers onto a front (700) and a back (701 ) side of a silicon substrate (40);
b) etching the said back side insulating layer (701 );
c) depositing and etching a first metal catalyst layer (703) on the said front side insulating layer (700);
d) depositing and etching a conductive layer (704) on the said first metal catalyst layer (703);
e) depositing and etching a second metal catalyst layer (705) on top of the said conductive layer (704);
f) etching the said silicon substrate (40) from the bottom to form an opening beneath the said front side insulating layer (700);
g) removing the said front side insulating layer (700) from a resistor region, said resistor region located between the said contact pads (50, 52); and h) growing of nanostructures at the said resistor region from the exposed metal catalyst (703, 705) areas.
Figure 8 shows a process flow in a fabrication process using a glass substrate and a multiple deposition and single etching step comprising the steps of:
a) depositing a first metal catalyst layer (703) on a substrate (40);
b) depositing a conductive layer (704) on the said first metal catalyst layer (703);
c) depositing a second metal catalyst layer (705) on top of the said conductive layer (704);
d) etching the said first metal catalyst layer (703), conductive layer (704) and second metal catalyst layer (705) simultaneously to form resistor and contact pad areas (50, 52);
e) removing the said second metal catalyst layer (705) from the said contact pad areas (50, 52);
f) depositing and etching a backside masking material (706) to be use as a mask during glass etching;
g) etching the said substrate (40) from the bottom to form an opening beneath a resistor region, said resistor region located between the said contact pads (50, 52);
h) growing of nanostructures at the said resistor region from the exposed metal catalyst (703, 705) areas.
The metal catalysts (703, 705) are deposited by physical or chemical vapour deposition (PVD or CVD) and made from any or a combination of: gold (Au), cobalt (Co), iron (Fe), nickel (Ni), indium (In) and copper (Cu). The conductive layer (704) is deposited by PVD or CVD and made from any or a combination of: gold (Au), platinum (Pt), nickel (Ni), tungsten (W), cobalt (Co) and copper (Cu). The said etching of the said first metal catalyst layer (703), conductive layer (704) and second metal catalyst layer (705) simultaneously is done with Argon (Ar) plasma or in a wet chemical solution. The said backside masking material (706) is selected from a group consisting and not limited to polymers, silicon, chrome (Cr), molybdenum (Mo), gold (Au) and silver (Ag). The said substrate (40) is done using hydrofluoric acid (HF) or combination with inductively couple plasma reactive ion etching (ICP-RIE) method with octafluorocyclobutane (C4F8) plasma. The said growing of nanostructures at the said resistor region is done using a method selected from the group consisting of chemical vapour deposition (CVD), metalorganic chemical vapour deposition (MOCVD), plasma enhanced chemical vapour deposition (PECVD), hot wire chemical vapour deposition (HWCVD), atomic layer deposition (ALD), electrochemical deposition, solution chemical deposition or combinations thereof.
Figure 9 shows a process flow in a fabrication process using a glass substrate and a multiple deposition and multiple etching step comprising the steps of:
a) depositing and etching a first metal catalyst layer (703) on a glass substrate (40);
b) depositing and etching a conductive layer (704) on the said first metal catalyst layer (703);
c) depositing and etching a second metal catalyst layer (705) on top of the said conductive layer (704);
d) depositing and etching a backside masking material (706) to be used as a mask during glass etching;
e) etching the glass substrate (40) from the bottom to form an opening beneath a resistor region, said resistor region located between the said contact pads (50, 52); and
f) growing of nanostructures at the said resistor region from the exposed metal catalyst (703, 705) areas.
The metal catalysts (703, 705) are deposited by physical or chemical vapour deposition (PVD or CVD) and made from any or a combination of: gold (Au), cobalt (Co), iron (Fe), nickel (Ni), indium (In) and copper (Cu). The said conductive layer (704) is deposited by PVD or CVD and made from any or a combination of: gold (Au), platinum (Pt), nickel (Ni), tungsten (W), cobalt (Co) and copper (Cu). The said etching of the said first metal catalyst layer (703), conductive layer (704) and second metal catalyst layer (705) simultaneously is done with Argon (Ar) plasma or in a wet chemical solution. The said backside masking material (706) is selected from a group consisting and not limited to polymers, silicon, chrome (Cr), molybdenum (Mo), gold (Au) and silver (Ag). The said etching of the said substrate (40) is done using hydrofluoric acid (HF) or combination with inductively couple plasma reactive ion etching (ICP-RIE) method with octafluorocyclobutane (C4F8) plasma. The said growing of nanostructures at the said resistor region is done using a method selected from the group consisting of chemical vapour deposition (CVD), metalorganic chemical vapour deposition (MOCVD), plasma enhanced chemical vapour deposition (PECVD), hot wire chemical vapour deposition (HWCVD), atomic layer deposition (ALD), electrochemical deposition, solution chemical deposition or combinations thereof. While several particularly preferred embodiments of the present invention have been described and illustrated, it should now be apparent to those skilled in the art that various changes and modifications can be made without departing from the
spirit and scope of the invention. Accordingly, the following claims are intended to embrace such changes, modifications, and areas of application that are within the spirit and scope of this invention.
Claims
A sensor device based on a change in electrical resistance comprising: a resistor structure (10) having two ends;
a plurality of nanostructures (20) attached to at least a portion of said resistor structure (10);
a pair of contact pads (50, 52), each contact pad located at each said end of the resistor structure (10);
a substrate (40) supporting each said end of the resistor structure (10); and
an insulating layer (30, 32) sandwiched between said substrate (40) and each said end of the resistor structure (10).
2. A sensor device based on a change in electrical resistance according to claim 1 wherein the said resistor structure (10) between each said contact pad (50, 52) comprises a long wire shaped in a serpentine fashion (12) to cover a larger area.
3. A sensor device based on a change in electrical resistance according to claim 1 wherein the said resistor structure (10) between each said contact pad (50, 52) comprises a plurality of wires running parallel to each other (14).
4. A sensor device based on a change in electrical resistance according to any of claims 1 to 3 wherein in operation, an electrical current is maintained along the said resistor structure (10) and the said nanostructures (20), upon detecting receptive ions, changes the resistance of the said resistor structure (10), said change in resistance measurable by an external measuring means. 5. A sensor device based on a change in electrical resistance according to any of claims 1 to 4 wherein the said nanostructures are either nanotubes or
nanowires selected from a group consisting and not limited to carbon nanotubes, silicon nanowires, tungsten nanowires, tungsten oxide nanowires, zinc oxide nanowires, indium oxide nanowires, tin oxide nanowires, gold nanowires or a combination thereof.
A sensor device based on a change in electrical resistance according to any of the preceding claims wherein the said nanostructures (20) may be either uni-directional (201 ) or multi-directional (202).
A method of fabricating a sensor device comprising the steps of:
a) depositing insulating layers onto a front (700) and a back (701 ) side of a substrate (40);
b) etching the said back side insulating layer (701);
c) depositing a first metal catalyst layer (703) on the said front side insulating layer (700);
d) depositing a conductive layer (704) on the said first metal catalyst layer (703);
e) depositing a second metal catalyst layer (705) on top of the said conductive layer (704);
f) etching the said first metal catalyst layer (703), conductive layer (704) and second metal catalyst layer (705) simultaneously to form resistor and contact pad areas (50, 52);
g) removing the said second metal catalyst layer (705) from the said contact pad areas (50, 52);
h) etching the said substrate (40) from the bottom to form an opening beneath the said front side insulating layer (700);
i) removing the said front side insulating layer (700) from a resistor region, said resistor region located between the said contact pads (50, 52); and
j) growing of nanostructures at the said resistor region from the exposed metal catalyst (703, 705) areas.
8. A method of fabricating a sensor device according to claim 7 wherein the said insulating layers (700, 701 ) are any or a combination of: silicon dioxide or silicon nitride deposited by physical or chemical vapour deposition; or silicon dioxide grown by a thermal oxidation method.
9. A method of fabricating a sensor device according to claim 7 or 8 wherein the said etching of the said back side insulating layer (701) is done using either Tetrafluoromethane (CF4) and Trifluoromethane (CHF3) plasma or in a hydrofluoric acid (HF) based chemical solution.
10. A method of fabricating a sensor device according to any of claims 7 to
9 wherein the said metal catalysts (703, 705) are deposited by physical or chemical vapour deposition (PVD or CVD) and made from any or a combination of: gold (Au), cobalt (Co), iron (Fe), nickel (Ni), indium (In) and copper (Cu).
11. A method of fabricating a sensor device according to any of claims 7 to
10 wherein the said conductive layer (704) is deposited by PVD or CVD and made from any or a combination of: gold (Au), platinum (Pt), nickel (Ni), tungsten (W), cobalt (Co) and copper (Cu).
12. A method of fabricating a sensor device according to any of claims 7 to
1 1 wherein the said etching of the said first metal catalyst layer (703), conductive layer (704) and second metal catalyst layer (705) simultaneously is done with Argon (Ar) plasma or in a wet chemical solution.
13. A method of fabricating a sensor device according to any of claims 7 to
12 wherein the said etching of the said substrate (40) is done using an inductively coupled plasma reactive ion etching (ICP-RIE) method with sulphur hexafluoride (SF6) based plasma, or with a wet chemical etchant of potassium hydroxide (KOH) or Tetramethylammonium Hydroxide (TMAH).
14. A method of fabricating a sensor device according to any of claims 7 to
13 wherein the said removing the said front side insulating layer (700) from a resistor region is done using buffered hydrofluoric acid (HF). 15. A method of fabricating a sensor device according to any of claims 7 to
14 wherein the said growing of nanostructures at the said resistor region is done using a method selected from the group consisting of chemical vapour deposition (CVD), metalorganic chemical vapour deposition (MOCVD), plasma enhanced chemical vapour deposition (PECVD), hot wire chemical vapour deposition (HWCVD), atomic layer deposition (ALD), electrochemical deposition, solution chemical deposition or combinations thereof.
A method of fabricating a sensor device comprising the steps of:
a) depositing insulating layers onto a front (700) and a back (701 ) side of a substrate (40);
b) etching the said back side insulating layer (701 );
c) depositing and etching a first metal catalyst layer (703) on the said front side insulating layer (700);
d) depositing and etching a conductive layer (704) on the said first metal catalyst layer (703);
e) depositing and etching a second metal catalyst layer (705) on top of the said conductive layer (704);
f) etching the said substrate (40) from the bottom to form an opening beneath the said front side insulating layer (700);
g) removing the said front side insulating layer (700) from a resistor region, said resistor region located between the said contact pads (50, 52); and
h) growing of nanostructures at the said resistor region from the exposed metal catalyst (703, 705) areas.
17. A method of fabricating a sensor device according to claim 16 wherein the said insulating layers (700, 701 ) are any or a combination of: silicon dioxide or silicon nitride deposited by physical or chemical vapour deposition; or silicon dioxide grown by a thermal oxidation method.
18. A method of fabricating a sensor device according to claim 16 or 17 wherein the said etching of the said back side insulating layer (701 ) is done using either Tetrafluoromethane (CF4) and Trifluoromethane (CHF3) plasma or in a hydrofluoric acid (HF) based chemical solution.
19. A method of fabricating a sensor device according to any of claims 16 to
18 wherein the said metal catalysts (703, 705) are deposited by physical or chemical vapour deposition (PVD or CVD) and made from any or a combination of: gold (Au), cobalt (Co), iron (Fe), nickel (Ni), indium (In) and copper (Cu).
20. A method of fabricating a sensor device according to any of claims 16 to
19 wherein the said conductive layer (704) is deposited by PVD or CVD and made from any or a combination of: gold (Au), platinum (Pt), nickel (Ni), tungsten (W), cobalt (Co) and copper (Cu).
21. A method of fabricating a sensor device according to any of claims 16 to
20 wherein the said etching of the said first metal catalyst layer (703), conductive layer (704) and second metal catalyst layer (705) simultaneously is done with Argon (Ar) plasma or in a wet chemical solution.
22. A method of fabricating a sensor device according to any of claims 16 to
21 wherein the said etching of the said substrate (40) is done using an inductively coupled plasma reactive ion etching (ICP-RIE) method with sulphur hexafluoride (SF6) based plasma, or with a wet chemical etchant of potassium hydroxide (KOH) or Tetramethylammonium Hydroxide (T AH).
23. A method of fabricating a sensor device according to any of claims 16 to 22 wherein the said removing the said front side insulating layer (700) from a resistor region is done using buffered hydrofluoric acid (HF).
24. A method of fabricating a sensor device according to any of claims 16 to 23 wherein the said growing of nanostructures at the said resistor region is done using a method selected from the group consisting of chemical vapour deposition (CVD), metalorganic chemical vapour deposition (MOCVD), plasma enhanced chemical vapour deposition (PECVD), hot wire chemical vapour deposition (HWCVD), atomic layer deposition (ALD), electrochemical deposition, solution chemical deposition or combinations thereof.
25. A method of fabricating a sensor device according to any of claims 7 to 23 wherein the said substrate is silicon.
26. A method of fabricating a sensor device comprising the steps of:
a) depositing a first metal catalyst layer (703) on a substrate (40);
b) depositing a conductive layer (704) on the said first metal catalyst layer (703);
c) depositing a second metal catalyst layer (705) on top of the said conductive layer (704);
d) etching the said first metal catalyst layer (703), conductive layer (704) and second metal catalyst layer (705) simultaneously to form resistor and contact pad areas (50, 52);
e) removing the said second metal catalyst layer (705) from the said contact pad areas (50, 52);
f) depositing and etching a backside masking material (706) to be use as a mask during glass etching
g) etching the said substrate (40) from the bottom to form an opening beneath a resistor region, said resistor region located between the said contact pads (50, 52);
h) growing of nanostructures at the said resistor region from the exposed metal catalyst (703, 705) areas.
27. A method of fabricating a sensor device according to claim 26 wherein the said metal catalysts (703, 705) are deposited by physical or chemical vapour deposition (PVD or CVD) and made from any or a combination of: gold (Au), cobalt (Co), iron (Fe), nickel (Ni), indium (In) and copper (Cu).
28. A method of fabricating a sensor device according to any of claims 26 to 27 wherein the said conductive layer (704) is deposited by PVD or CVD and made from any or a combination of: gold (Au), platinum (Pt), nickel (Ni), tungsten (W), cobalt (Co) and copper (Cu).
29. A method of fabricating a sensor device according to any of claims 26 to 28 wherein the said etching of the said first metal catalyst layer (703), conductive layer (704) and second metal catalyst layer (705) simultaneously is done with Argon (Ar) plasma or in a wet chemical solution.
30. A method of fabricating a sensor device according to any of claims 26 to 29 wherein the said backside masking material (706) is selected from a group consisting and not limited to polymers, silicon, chrome (Cr), molybdenum (Mo), gold (Au) and silver (Ag).
31. A method of fabricating a sensor device according to any of claims 26 to 30 wherein the said etching of the said substrate (40) is done using hydrofluoric acid (HF) or combination with inductively couple plasma reactive ion etching (ICP-RIE) method with octafluorocyclobutane (C4F8) plasma. 32. A method of fabricating a sensor device according to any of claims 26 to 31 wherein the said growing of nanostructures at the said resistor region is done using a method selected from the group consisting of chemical vapour
deposition (CVD), metalorganic chemical vapour deposition (MOCVD), plasma enhanced chemical vapour deposition (PECVD), hot wire chemical vapour deposition (HWCVD), atomic layer deposition (ALD), electrochemical deposition, solution chemical deposition or combinations thereof.
33. A method of fabricating a sensor device comprising the steps of:
a) depositing and etching a first metal catalyst layer (703) on a substrate (40);
b) depositing and etching a conductive layer (704) on the said first metal catalyst layer (703);
c) depositing and etching a second metal catalyst layer (705) on top of the said conductive layer (704);
d) depositing and etching a backside masking material (706) to be used as a mask during glass etching;
e) etching the said substrate (40) from the bottom to form an opening beneath a resistor region, said resistor region located between the said contact pads (50, 52);
f) growing of nanostructures at the said resistor region from the exposed metal catalyst (703, 705) areas.
34. A method of fabricating a sensor device according to claim 33 wherein the said metal catalysts (703, 705) are deposited by physical or chemical vapour deposition (PVD or CVD) and made from any or a combination of: gold (Au), cobalt (Co), iron (Fe), nickel (Ni), indium (In) and copper (Cu).
35. A method of fabricating a sensor device according to any of claims 33 to 34 wherein the said conductive layer (704) is deposited by PVD or CVD and made from any or a combination of: gold (Au), platinum (Pt), nickel (Ni), tungsten (W), cobalt (Co) and copper (Cu).
36. A method of fabricating a sensor device according to any of claims 33 to
35 wherein the said etching of the said first metal catalyst layer (703), conductive layer (704) and second metal catalyst layer (705) simultaneously is done with Argon (Ar) plasma or in a wet chemical solution.
37. A method of fabricating a sensor device according to any of claims 33 to
36 wherein the said backside masking material (706) is selected from a group consisting and not limited to polymers, silicon, chrome (Cr), molybdenum (Mo), gold (Au) and silver (Ag).
38. A method of fabricating a sensor device according to any of claims 33 to
37 wherein the said etching of the said substrate (40) is done using hydrofluoric acid (HF) or combination with inductively couple plasma reactive ion etching (ICP-RIE) method with octafluorocyclobutane (C4F8) plasma.
39. A method of fabricating a sensor device according to any of claims 33 to
38 wherein the said growing of nanostructures at the said resistor region is done using a method selected from the group consisting of chemical vapour deposition (CVD), metalorganic chemical vapour deposition (MOCVD), plasma enhanced chemical vapour deposition (PECVD), hot wire chemical vapour deposition (HWCVD), atomic layer deposition (ALD), electrochemical deposition, solution chemical deposition or combinations thereof.
40. A method of fabricating a sensor device according to any of claims 26 to
39 wherein the said substrate is glass.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| MYPI2010005723 | 2010-12-02 | ||
| MYPI2010005723A MY163139A (en) | 2010-12-02 | 2010-12-02 | Resistive ion sensing device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2012074367A1 true WO2012074367A1 (en) | 2012-06-07 |
Family
ID=46172127
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/MY2011/000151 Ceased WO2012074367A1 (en) | 2010-12-02 | 2011-06-24 | Resistive ion sensing device |
Country Status (2)
| Country | Link |
|---|---|
| MY (1) | MY163139A (en) |
| WO (1) | WO2012074367A1 (en) |
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| EP3346263A1 (en) * | 2017-01-09 | 2018-07-11 | Mobiosense Corp. | Biosensor device |
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| US10259704B2 (en) | 2016-04-07 | 2019-04-16 | Regents Of The University Of Minnesota | Nanopillar-based articles and methods of manufacture |
| US10265683B2 (en) | 2006-05-19 | 2019-04-23 | Massachusetts Institute Of Technology | Continuous process for the production of nanostructures including nanotubes |
| US10350837B2 (en) | 2016-05-31 | 2019-07-16 | Massachusetts Institute Of Technology | Composite articles comprising non-linear elongated nanostructures and associated methods |
| US10399316B2 (en) | 2006-05-19 | 2019-09-03 | Massachusetts Institute Of Technology | Nanostructure-reinforced composite articles and methods |
| US11031657B2 (en) | 2017-11-28 | 2021-06-08 | Massachusetts Institute Of Technology | Separators comprising elongated nanostructures and associated devices and methods, including devices and methods for energy storage and/or use |
| US11372118B2 (en) | 2016-09-09 | 2022-06-28 | Northeastern University | Ion and radiation detection devices based on carbon nanomaterials and two-dimensional nanomaterials |
| US11760848B2 (en) | 2017-09-15 | 2023-09-19 | Massachusetts Institute Of Technology | Low-defect fabrication of composite materials |
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| US20070062812A1 (en) * | 2003-07-25 | 2007-03-22 | Heribert Weber | Gas sensor and method for the production thereof |
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| US10906285B2 (en) | 2006-05-19 | 2021-02-02 | Massachusetts Institute Of Technology | Nanostructure-reinforced composite articles and methods |
| US11787691B2 (en) | 2006-05-19 | 2023-10-17 | Massachusetts Institute Of Technology | Continuous process for the production of nanostructures including nanotubes |
| US10265683B2 (en) | 2006-05-19 | 2019-04-23 | Massachusetts Institute Of Technology | Continuous process for the production of nanostructures including nanotubes |
| US11458718B2 (en) | 2006-05-19 | 2022-10-04 | Massachusetts Institute Of Technology | Nanostructure-reinforced composite articles and methods |
| US10399316B2 (en) | 2006-05-19 | 2019-09-03 | Massachusetts Institute Of Technology | Nanostructure-reinforced composite articles and methods |
| US10195797B2 (en) | 2013-02-28 | 2019-02-05 | N12 Technologies, Inc. | Cartridge-based dispensing of nanostructure films |
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| US10259704B2 (en) | 2016-04-07 | 2019-04-16 | Regents Of The University Of Minnesota | Nanopillar-based articles and methods of manufacture |
| US10350837B2 (en) | 2016-05-31 | 2019-07-16 | Massachusetts Institute Of Technology | Composite articles comprising non-linear elongated nanostructures and associated methods |
| US11372118B2 (en) | 2016-09-09 | 2022-06-28 | Northeastern University | Ion and radiation detection devices based on carbon nanomaterials and two-dimensional nanomaterials |
| EP3346263A1 (en) * | 2017-01-09 | 2018-07-11 | Mobiosense Corp. | Biosensor device |
| US11760848B2 (en) | 2017-09-15 | 2023-09-19 | Massachusetts Institute Of Technology | Low-defect fabrication of composite materials |
| US12215206B2 (en) | 2017-09-15 | 2025-02-04 | Massachusetts Institute Of Technology | Low-defect fabrication of composite materials |
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| Publication number | Publication date |
|---|---|
| MY163139A (en) | 2017-08-15 |
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