# US 9,752,972 B2 · Transistor-type viscosity sensor, and viscosity measurement system and viscosity measuring method using the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,752,972 B2 - Document ID: US9752972B2 - Status: Granted - Kind: B2 - Application number: 14/298,999 - Filed: 2014-06-09 - Published: 2015-09-10 - Granted: 2017-09-05 - Earliest claimed: 2014-03-07 - Assignees: National Tsing Hua University - Applicants: National Tsing Hua university - Inventors: Yu-Lin Wang; Jen-Inn Chyi; Jung-Ying Fang - Web page: https://patentgrep.com/patent/US9752972B2 ## CPC - G01N 11/02: by measuring flow of the material - G01N 11/00: Investigating flow properties of materials, e.g. viscosity, plasticity; Analysing materials by determining flow properties - G01N 2011/0066: {electrical properties} - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract A viscosity measurement system, which is for measuring the viscosity of a fluid, comprises a transistor-type viscosity sensor, an electrical measurement unit, and a processing unit. The transistor-type viscosity sensor includes a semiconductor structure, a source terminal, and a drain terminal. The semiconductor structure includes a GaN layer and an AlGaN layer disposed on the GaN layer. The portion of the semiconductor structure that is between the source terminal and the drain terminal has a gate region, which has an exposed surface for being in contact with the fluid. The electrical measurement unit is in electrical connection with the source terminal and the drain terminal and for measuring an electronic signal of the semiconductor structure. The processing unit is coupled to the electrical measurement unit and for determining the viscosity of the fluid according to the electronic signal measured. ## Claims ### Claim 1 A viscosity measurement system, for measuring the viscosity of a fluid with a dipole moment, the viscosity measurement system comprising: a transistor-type viscosity sensor, comprising: a semiconductor structure, comprising a GaN layer and an AlGaN layer disposed on the GaN layer; a source terminal, in ohmic contact with the AlGaN layer; a drain terminal, in ohmic contact with the AlGaN layer; and wherein the portion of the semiconductor structure that is between the source terminal and the drain terminal has a gate region, the gate region having an exposed surface for being in contact with the fluid with the dipole moment; an electrical measurement unit, in electrical connection with the source terminal and the drain terminal, for measuring an electronic signal of the semiconductor structure; and a processing unit, coupled to the electrical measurement unit, for determining the viscosity of the fluid with the dipole moment according to the electronic signal measured by the electrical measurement unit. ### Claim 2 (depends on 1) The viscosity measurement system of claim 1, wherein the electrical measurement unit is for measuring a current fluctuation of the semiconductor structure at a determined drain-source bias, and the processing unit is for determining the viscosity of the fluid according to the current fluctuation measured by the electrical measurement unit. ### Claim 3 (depends on 2) The viscosity measurement system of claim 2, wherein the processing unit includes a data storage module for storing a look-up datum, the content of which includes the relationship between the viscosity of the fluid and the current fluctuation of the semiconductor structure, and the processing unit is for determining the viscosity of the fluid based on the look-up datum. ### Claim 4 (depends on 1) The viscosity measurement system of claim 1, wherein the fluid has a dipole moment, which ranges from 1 to 5 debyes. ### Claim 5 (depends on 1) The viscosity measurement system of claim 1, wherein the exposed surface of the gate region has a width of 27 to 33 micrometers. ### Claim 6 (depends on 1) The viscosity measurement system of claim 1, wherein the mole percentage of Al of the AlGaN layer is 22% to 28%, and the thickness of the AlGaN layer is 13.5 to 16.5 nanometers. ### Claim 7 (depends on 1) The viscosity measurement system of claim 1, wherein the semiconductor structure is formed of an epitaxy wafer structure. ### Claim 8 (depends on 1) The viscosity measurement system of claim 1, wherein the semiconductor structure further comprises a substrate, and the GaN layer is disposed on the substrate. ### Claim 9 (depends on 1) The viscosity measurement system of claim 1, wherein the semiconductor structure further comprises a gold layer disposed on the portion of the AlGaN layer that comprises the gate region. ### Claim 10 (depends on 1) The viscosity measurement system of claim 1, wherein the semiconductor structure further comprises a passivation layer covering at least the source terminal and the drain terminal and exposing the exposed surface of the gate region. ### Claim 11 A transistor-type viscosity sensor, for measuring the viscosity of a fluid with a dipole moment, the transistor-type viscosity sensor comprising: a semiconductor structure, comprising a GaN layer and an AlGaN layer disposed on the GaN layer; a source terminal, in ohmic contact with the AlGaN layer; and a drain terminal, in ohmic contact with the AlGaN layer; wherein the portion of the semiconductor structure that is between the source terminal and the drain terminal has a gate region, the gate region having an exposed surface for being in contact with the fluid with the dipole moment; wherein when the exposed surface of the gate region is in contact with the fluid with the dipole moment, a fluctuation of the current that is flowing in the semiconductor structure is generated by the molecular motions of the fluid with the dipole moment. ### Claim 12 (depends on 11) The transistor-type viscosity sensor of claim 11, wherein the fluid has a dipole moment, which ranges from 1 to 5 debyes. ### Claim 13 (depends on 11) The transistor-type viscosity sensor of claim 11, wherein the exposed surface of the gate region has a width of 27 to 33 micrometers. ### Claim 14 (depends on 11) The transistor-type viscosity sensor of claim 11, wherein the mole percentage of Al of the AlGaN layer is 22% to 28%, and the thickness of the AlGaN layer is 13.5 to 16.5 nanometers. ### Claim 15 (depends on 11) The transistor-type viscosity sensor of claim 11, wherein the semiconductor structure is formed of an epitaxy wafer structure. ### Claim 16 (depends on 11) The transistor-type viscosity sensor of claim 11, wherein the semiconductor structure further comprises a substrate, and the GaN layer is disposed on the substrate. ### Claim 17 (depends on 11) The transistor-type viscosity sensor of claim 11, wherein the semiconductor structure further comprises a gold layer disposed on the portion of the AlGaN layer that comprises the gate region. ### Claim 18 (depends on 11) The transistor-type viscosity sensor of claim 11, wherein the semiconductor structure further comprises a passivation layer covering at least the source terminal and the drain terminal and exposing the exposed surface of the gate region. ### Claim 19 A viscosity measuring method, for measuring the viscosity of a fluid with a dipole moment, the viscosity measuring method comprising the steps of: providing a transistor-type viscosity sensor, wherein the transistor-type viscosity sensor comprises a semiconductor structure, a source terminal, and a drain terminal, the semiconductor structure includes a GaN layer and an AlGaN layer disposed on the GaN layer, the source terminal and the drain terminal respectively are in ohmic contact with the AlGaN layer, the portion of the semiconductor structure that is between the source terminal and the drain terminal has a gate region, and the gate region has an exposed surface; putting the fluid with the dipole moment into contact with the exposed surface of the gate region; measuring an electronic signal of the semiconductor structure; and determining the viscosity of the fluid with the dipole moment according to the electronic signal measured. ### Claim 20 (depends on 19) The viscosity measuring method of claim 19, wherein the measuring electronic signal of the semiconductor structure comprises: measuring a current fluctuation of the semiconductor structure at a determined drain-source bias; and wherein the determining the viscosity of the fluid comprises: determining the viscosity of the fluid according to the current fluctuation measured. ### Claim 21 (depends on 20) The viscosity measuring method of claim 20, wherein the determining the viscosity of the fluid comprises: determining the viscosity of the fluid based on a look-up datum, the content of which includes the relationship between the viscosity of the fluid and the current fluctuation of the semiconductor structure. ### Claim 22 (depends on 19) The viscosity measuring method of claim 19, wherein the putting the fluid into contact with the exposed surface comprises: submerging the transistor-type viscosity sensor in the fluid. ### Claim 23 (depends on 19) The viscosity measuring method of claim 19, wherein the putting the fluid into contact with the exposed surface comprises: dropping a portion of the fluid on the exposed surface of the gate region. ### Claim 24 (depends on 23) The viscosity measuring method of claim 23, wherein the portion of the fluid that is dropped on the exposed surface has a volume of 1 to 10 microliters. ### Claim 25 (depends on 19) The viscosity measuring method of claim 19, wherein the fluid has a dipole moment which ranges from 1 to 5 debyes. ### Claim 26 (depends on 19) The viscosity measuring method of claim 19, wherein the exposed surface of the gate region has a width of 27 to 33 micrometers. ### Claim 27 (depends on 19) The viscosity measuring method of claim 19, wherein the mole percentage of Al of the AlGaN layer is 22% to 28%, and the thickness of the AlGaN layer is 13.5 to 16.5 nanometers. ### Claim 28 (depends on 19) The viscosity measuring method of claim 19, wherein the semiconductor structure is formed of an epitaxy wafer structure. ### Claim 29 (depends on 19) The viscosity measuring method of claim 19, wherein the semiconductor structure further comprises a gold layer disposed on the portion of the AlGaN layer that comprises the gate region. ### Claim 30 (depends on 19) The viscosity measuring method of claim 19, wherein the semiconductor structure further comprises a passivation layer covering at least the source terminal and the drain terminal and exposing the exposed surface of the gate region.