# US 9,040,929 B2 · Charge sensors using inverted lateral bipolar junction transistors > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,040,929 B2 - Document ID: US9040929B2 - Status: Granted - Kind: B2 - Application number: 13/561,671 - Filed: 2012-07-30 - Published: 2014-01-30 - Granted: 2015-05-26 - Earliest claimed: 2012-07-30 - Assignees: International Business Machines Corporation - Applicants: Jin Cai; Tak H. Ning; Jeng-Bang Yau; Sufi Zafar - Inventors: Jin Cai; Tak H. Ning; Jeng-Bang Yau; Sufi Zafar - Web page: https://patentgrep.com/patent/US9040929B2 ## CPC - G01T 1/247: {Detector read-out circuitry (for processing gain or off-set correction H04N)} - G01N 27/403: Cells and electrode assemblies - G01T 3/08: with semiconductor detectors - H10F 30/245: {Bipolar phototransistors} - H10F 30/29: the devices being sensitive to radiation having very short wavelengths, e.g. X-rays, gamma-rays or corpuscular radiation - H10F 30/295: Surface barrier or shallow PN junction radiation detectors, e.g. surface barrier alpha-particle detectors - H10F 77/14: Shape of semiconductor bodies; Shapes, relative sizes or dispositions of semiconductor regions within semiconductor bodies - H10F 77/206: {for devices having potential barriers} - H10F 39/197: {Bipolar transistor image sensors} - G01T: MEASUREMENT OF NUCLEAR OR X-RADIATION (radiation analysis of materials, mass spectrometry G01N23/00; tubes for determining the presence, intensity, density or energy of radiation or particles H01J47/00) - 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) - H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION ## Abstract A sensor includes a collector, an emitter and a base-region barrier formed as an inverted bipolar junction transistor having a base substrate forming a base electrode to activate the inverted bipolar junction transistor. A level surface is formed by the collector, the emitter and the base-region barrier opposite the base substrate such that when the level surface is exposed to charge, the charge is measured during operation of the bipolar junction transistor. ## Claims ### Claim 1 A sensor, comprising: a collector, an emitter and a base-region barrier formed as an inverted bipolar junction transistor having a base substrate forming a base electrode to activate the inverted bipolar junction transistor; a level surface formed by the collector, the emitter and the base-region barrier opposite the base substrate such that when the level surface is exposed to charge, the charge is measured during operation of the bipolar junction transistor; and a detection layer directly on an entirety of the level surface. ### Claim 2 (depends on 1) The sensor as recited in claim 1, wherein the base electrode is selectively activated to enable the inverted bipolar junction transistor to make a measurement. ### Claim 3 (depends on 1) The sensor as recited in claim 1, wherein accumulated charge at or near the level surface affects a collector current of the inverted bipolar junction transistor. ### Claim 4 (depends on 3) The sensor as recited in claim 3, wherein an exponential relationship exists between the collector current and a voltage caused by the accumulated charge. ### Claim 5 (depends on 1) The sensor as recited in claim 1, wherein an accumulated charge in the detection layer is proportional to a dose or number of interactions with material to be measured at the detection layer. ### Claim 6 (depends on 5) The sensor as recited in claim 5, wherein the detection layer includes an accumulation layer and a conversion layer such that the conversion layer turns interactions therewith into charge which is accumulated in the accumulation layer. ### Claim 7 (depends on 6) The sensor as recited in claim 6, wherein the conversion layer converts incident radiation into charge, the radiation including at least one of alpha particles, beta particles, protons, neutrons, and electromagnetic radiation. ### Claim 8 A sensor, comprising: a collector, an emitter and a base-region barrier formed as an inverted bipolar junction transistor having a base substrate forming a base electrode to activate the inverted bipolar junction; a level surface formed by the collector, the emitter and the base-region barrier opposite the base substrate such that when the level surface is exposed to charge, the charge is measured during operation of the bipolar junction transistor; and a detection layer disposed over an entirety of the level surface and configured to interface with an item to be measured such that interaction or contact with the substance generates the charge measurable by the bipolar junction transistor. ### Claim 9 (depends on 8) The sensor as recited in claim 8, wherein the base electrode is selectively activated to enable the inverted bipolar junction transistor to make a measurement. ### Claim 10 (depends on 8) The sensor as recited in claim 8, wherein accumulated charge at or near the level surface affects a collector current of the inverted bipolar junction transistor. ### Claim 11 (depends on 10) The sensor as recited in claim 10, wherein an exponential relationship exists between the collector current and a voltage caused by the accumulated charge. ### Claim 12 (depends on 8) The sensor as recited in claim 8, wherein the detection layer stores an accumulated charge, which is proportional to a dose or number of interactions with the item to be measured. ### Claim 13 (depends on 8) The sensor as recited in claim 8, wherein the detection layer includes an accumulation layer and a conversion layer such that the conversion layer turns interactions therewith into charge which is accumulated in the accumulation layer. ### Claim 14 (depends on 13) The sensor as recited in claim 13, wherein the conversion layer converts incident radiation into charge, the radiation including at least one of alpha particles, beta particles, protons, neutrons, and electromagnetic radiation. ### Claim 15 A sensor, comprising: a base substrate including a monocrystalline semiconductor material; a base-region barrier extending from the base substrate and including a monocrystalline structure having a same dopant conductivity as the base substrate; an emitter contacting a first lateral side of the base-region barrier; and a collector contacting a second lateral side opposite the emitter to form a bipolar junction transistor, the emitter and collector being spaced from the base substrate by a buried dielectric layer, the collector, the emitter and the base-region barrier forming a level surface opposite the base substrate; and a detection layer disposed over an entirety of the level surface such that when the detection layer is exposed to charge, the charge is measured during operation of the bipolar junction transistor. ### Claim 16 (depends on 15) The sensor as recited in claim 15, wherein the base substrate forms a base electrode to selectively enable operation of the inverted bipolar junction transistor and accumulated charge at or near the level surface affects a collector current of the inverted bipolar junction transistor and further wherein an exponential relationship exists between the collector current and a voltage caused by the accumulated charge. ### Claim 17 (depends on 15) The sensor as recited in claim 15, wherein the detection layer includes an accumulation layer and a conversion layer such that the conversion layer turns interactions therewith into charge which is accumulated in the accumulation layer, wherein the conversion layer converts incident radiation into charge, the radiation including at least one of alpha particles, beta particles, protons, neutrons, and electromagnetic radiation.