# US 2017/0253992 A1 · Stable P-Type Zinc Oxide and Bandgap Engineered Zinc Oxide and Other Oxide Systems > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0253992 A1 - Document ID: US20170253992A1 - Status: Published application - Kind: A1 - Application number: 15/446,418 - Filed: 2017-03-01 - Published: 2017-09-07 - Earliest claimed: 2016-03-01 - Inventors: Eric A Burgett - Web page: https://patentgrep.com/patent/US20170253992A1 ## CPC - C30B 25/165: {the flow of the reactive gases} - C23C 14/0021: {Reactive sputtering or evaporation} - C23C 14/021: {Cleaning or etching treatments} - C23C 14/083: {of refractory metals or yttrium} - C23C 14/086: {of zinc, germanium, cadmium, indium, tin, thallium or bismuth} - C23C 14/24: Vacuum evaporation - C23C 16/0227: {by cleaning or etching} - C23C 16/405: {of refractory metals or yttrium} - C23C 16/407: {of zinc, germanium, cadmium, indium, tin, thallium or bismuth} - C23C 16/45523: {Pulsed gas flow or change of composition over time} - C23C 16/4584: {the substrate being rotated} - C30B 25/186: {being specially pre-treated by, e.g. chemical or physical means} - C30B 29/16: Oxides - H10P 14/22: using physical deposition, e.g. vacuum deposition or sputtering - H10P 14/24: using chemical vapour deposition [CVD] - H10P 14/29: {characterised by the substrates} - H10P 14/3426: {Oxides} - H10P 14/3434: {being oxide semiconductor materials (Group IIB-VIA semiconductor materials H10P14/3424)} - H10P 14/3444: {P-type} - H10P 14/36: {characterised by treatments done before the formation of the materials} - C30B: SINGLE-CRYSTAL GROWTH (by using ultra-high pressure, e.g. for the formation of diamonds, B01J3/06); UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL (zone-refining of metals or alloys C22B); PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (casting of metals, casting of other substances by the same processes or devices B22D; working of plastics B29; modifying the physical structure of metals or alloys C21D, C22F); SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (for producing semiconductor devices or parts thereof H10); APPARATUS THEREFOR - C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04) - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 ## Abstract Zinc oxide (ZnO) inherently exhibits n-type behavior due to naturally-occurring oxygen vacancies and zinc interstitials. Many other metal oxide systems have been found to exhibit similar semiconductor characteristics as zinc oxide, i.e. inherently n-type, including other metal oxide semiconductors such as GaO, MgO, CuO, etc. or ternary alloys with zinc oxide such as MgZnO, CdZnO, GaZnO, etc. The method described herein creates stable p-type ZnO or other metal oxide semiconductor materials, by using an oxygen scavenger material, e.g. calcium or tungsten, that is introduced during the formation of the material which preferentially scavenges oxygen resulting in an abundance of zinc vacancies, which act as holes, and induces stable p-type behavior without alloying or being incorporated into the semiconductor material itself. Three deposition techniques to deposit this stable form of p-type material and p+ type material are described. ## Claims ### Claim 1 A method for producing stable zinc oxide based semiconductor materials exhibiting p-type characteristics, said method comprising the steps of: providing a substrate material to receive deposition of a p-type zinc oxide material; cleaning said substrate by removing excess oxygen from a surface of said substrate material; placing said substrate material in a chemical vapor deposition chamber; mounting said substrate material above a p-type zinc oxide precursor; providing a heating device below said mounted substrate material; placing p-type zinc oxide precursor material in said heating device and heating said p-type precursor zinc oxide material to remove excess oxygen; continuing to heat p-type zinc oxide precursor material until sublimation of said p-type zinc oxide precursor material occurs; providing and heating an oxygen scavenger refractory metal material until sublimation of said oxygen scavenger material occurs to remove excess oxygen from said p-type zinc oxide precursor, depositing zinc oxide material onto said substrate material. ### Claim 2 (depends on 1) The method set forth in claim 1 wherein said step of cleaning said substrate material is selected from the group of ultrasonic cleaning, reactive ion-etching, plasma enhanced ion etching, acid etching, plasma cleaning using O2, Ar, CH2, C2H2, CF4, CF3H, or the like; plasma ashing/etching; ion milling, glancing angle ion milling, mechanical lapping and polishing, rapid thermal annealing in reactive or inert atmosphere, and rapid thermal annealing in a hydrogen or vacuum atmosphere. ### Claim 3 (depends on 1) The method set forth in claim 1, wherein said substrate material is selected from the group consisting of Zinc Oxide (ZnO), gallium nitride (GaN), Boron Nitride (BN), Aluminum Nitride (AlN), Gallium Phosphide (GaP), Gallium Arsenide (GaAs), Gallium Antimonide (GaSb), Indium Nitride (InN), Indium Phosphide (InP), Indium Arsenide (InAs), Cadmium Sulfide (CdS), Zinc Sulfide (ZnS), Titanium Oxide (TiO2), Cupric Oxide (CuO, Cu2O), Uranium oxide (UO2) sapphire (Al2O3), quartz (SiO2), gallium oxide (GaO), organic semiconductor materials (PEDOT, Anthracene, pentacene), Indium Tin Oxide (ITO), and Silicon Carbide (SiC). ### Claim 4 (depends on 1) The method set forth in claim 1, further including the step of rotating said substrate material within said vapor deposition chamber. ### Claim 5 (depends on 1) The method set forth in claim 1, further including the step of subsequently changing a ratio of the quantity of sublimating zinc oxide with respect to that of the refractory metal material in order to remove a greater quantity of excess oxygen from said p-type zinc oxide precursor. ### Claim 6 (depends on 1) The method set forth in claim 1, further including the step of depositing an oxygen scavenging layer on an outer surface of said coated substrate. ### Claim 7 (depends on 6) The method set forth in claim 6, wherein said oxygen scavenging layer is formed from a refractory metal selected from the group consisting of calcium, tungsten, strontium, erbium, aluminum, titanium, uranium, and thorium. ### Claim 8 (depends on 7) The method set forth in claim 7, further including the step of capping said oxygen scavenging layer with a protective noble metal layer by depositing said noble metal layer over said oxygen scavenging layer within said chemical vapor deposition chamber. ### Claim 9 A method for producing stable zinc oxide based semiconductor materials exhibiting p-type characteristics, said method comprising the steps of: providing a substrate material to receive deposition of a p-type zinc oxide material; cleaning said substrate by removing excess oxygen from a surface of said substrate material; placing said substrate material in a chemical vapor deposition chamber; heating said substrate material; providing a zinc precursor, an oxygen precursor and a refractory metal precursor, each said precursor in gas form; providing a flow of said precursor gas, wherein said precursor gas flows across said substrate material in a measured, fixed ratio between zinc precursor, oxygen precursor and refractory metal precursor. ### Claim 10 (depends on 9) The method set forth in claim 9, further including the step of subsequently changing said precursor gas ratio by increasing an amount of said refractory metal precursor, and decreasing an amount of said oxygen precursor, and allowing precursor gas flow to continue over said substrate. ### Claim 11 (depends on 9) The method set forth in claim 9, further including the step of depositing an oxygen scavenging layer on an outer surface of said coated substrate. ### Claim 12 (depends on 11) The method set forth in claim 11, wherein said oxygen scavenging layer is formed from a refractory metal selected from the group consisting of calcium, tungsten, strontium, erbium, aluminum, titanium, uranium, and thorium. ### Claim 13 (depends on 12) The method set forth in claim 12, further including the step of capping said oxygen scavenging layer with a protective noble metal layer by depositing said noble metal layer over said oxygen scavenging layer within said chemical vapor deposition chamber. ### Claim 14 (depends on 9) The method set forth in claim 9, further including the step of rotating said substrate material within said chemical vapor deposition chamber. ### Claim 15 A method for producing stable zinc oxide based semiconductor materials exhibiting p-type characteristics, said method comprising the steps of: providing a substrate material to receive deposition of a p-type zinc oxide material; cleaning said substrate by removing excess oxygen from a surface of said substrate material; placing said substrate material in a chemical vapor deposition chamber; heating substrate; providing a zinc precursor, an oxygen precursor and a refractory metal precursor in gas form; providing a pulse flow of said zinc and oxygen precursor in a fixed ratio; stopping said pulse flow of zinc and oxygen precursor and subsequently providing a pulse flow of refractory metal precursor; alternating pulse flow of zinc and oxygen precursor with pulse flow of refractory metal precursor, wherein said precursor gases alternately flow across said substrate material in a fixed ratio between said zinc precursor, oxygen precursor and refractory metal precursor. ### Claim 16 (depends on 15) The method set forth in claim 15, further including the step of depositing an oxygen scavenging layer on an outer surface of said coated substrate. ### Claim 17 (depends on 16) The method set forth in claim 16, wherein said oxygen scavenging layer is formed from a refractory metal selected from the group consisting of calcium, tungsten, strontium, erbium, aluminum, titanium, uranium, and thorium. ### Claim 18 (depends on 17) The method set forth in claim 17, further including the step of capping said oxygen scavenging layer with a protective noble metal layer by depositing said noble metal layer over said oxygen scavenging layer within said chemical vapor deposition chamber. ### Claim 19 (depends on 15) The method set forth in claim 15 wherein said step of cleaning said substrate material is selected from the group of ultrasonic cleaning, reactive ion-etching, plasma enhanced ion etching, acid etching, plasma cleaning using O2, Ar, CH2, C2H2, CF4, CF3H, or the like; plasma ashing/etching; ion milling, glancing angle ion milling, mechanical lapping and polishing, rapid thermal annealing in reactive or inert atmosphere, and rapid thermal annealing in a hydrogen or vacuum atmosphere. ### Claim 20 (depends on 15) The method set forth in claim 15, wherein said substrate material is selected from the group consisting of Zinc Oxide (ZnO), gallium nitride (GaN), Boron Nitride (BN), Aluminum Nitride (AlN), Gallium Phosphide (GaP), Gallium Arsenide (GaAs), Gallium Antimonide (GaSb), Indium Nitride (InN), Indium Phosphide (InP), Indium Arsenide (InAs), Cadmium Sulfide (CdS), Zinc Sulfide (ZnS), Titanium Oxide (TiO2), Cupric Oxide (CuO, Cu2O), Uranium oxide (UO2) sapphire (Al2O3), quartz (SiO2), gallium oxide (GaO), organic semiconductor materials (PEDOT, Anthracene, pentacene), Indium Tin Oxide (ITO), and Silicon Carbide (SiC). ### Claim 21 (depends on 15) The method set forth in claim 15, further including the step of rotating said substrate material within said chemical vapor deposition chamber. ### Claim 22 (depends on 15) The method set forth in claim 15, further including the step of subsequently changing the ratio of the pulse flow of said zinc and oxygen precursor in a fixed ratio with respect to that of the pulse flow of refractory metal precursor in order to remove a greater quantity of excess oxygen from said p-type zinc and oxygen precursor pulse.