WO2022240357A1 - Dysprosium scandate films, methods of fabrication and uses thereof - Google Patents
Dysprosium scandate films, methods of fabrication and uses thereof Download PDFInfo
- Publication number
- WO2022240357A1 WO2022240357A1 PCT/SG2022/050300 SG2022050300W WO2022240357A1 WO 2022240357 A1 WO2022240357 A1 WO 2022240357A1 SG 2022050300 W SG2022050300 W SG 2022050300W WO 2022240357 A1 WO2022240357 A1 WO 2022240357A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- layer
- dso
- silicon wafer
- etched surface
- ysz
- Prior art date
Links
- 229910052692 Dysprosium Inorganic materials 0.000 title claims abstract description 34
- KBQHZAAAGSGFKK-UHFFFAOYSA-N dysprosium atom Chemical compound [Dy] KBQHZAAAGSGFKK-UHFFFAOYSA-N 0.000 title claims abstract description 34
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 15
- 238000000034 method Methods 0.000 title claims description 32
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 97
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 97
- 239000010703 silicon Substances 0.000 claims abstract description 97
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims abstract description 64
- 229910001233 yttria-stabilized zirconia Inorganic materials 0.000 claims abstract description 54
- 238000000151 deposition Methods 0.000 claims abstract description 22
- 229910000422 cerium(IV) oxide Inorganic materials 0.000 claims abstract description 15
- 125000003545 alkoxy group Chemical group 0.000 claims abstract description 13
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims description 24
- 238000004549 pulsed laser deposition Methods 0.000 claims description 23
- 238000002441 X-ray diffraction Methods 0.000 claims description 19
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims description 12
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 11
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims description 10
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 claims description 10
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 10
- 239000001301 oxygen Substances 0.000 claims description 10
- 229910052760 oxygen Inorganic materials 0.000 claims description 10
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 9
- BDERNNFJNOPAEC-UHFFFAOYSA-N propan-1-ol Chemical compound CCCO BDERNNFJNOPAEC-UHFFFAOYSA-N 0.000 claims description 8
- 239000011261 inert gas Substances 0.000 claims description 6
- 235000011114 ammonium hydroxide Nutrition 0.000 claims description 5
- 238000004140 cleaning Methods 0.000 claims description 5
- 229960004592 isopropanol Drugs 0.000 claims description 5
- 241000252506 Characiformes Species 0.000 claims description 4
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 claims description 3
- CETPSERCERDGAM-UHFFFAOYSA-N ceric oxide Chemical compound O=[Ce]=O CETPSERCERDGAM-UHFFFAOYSA-N 0.000 abstract 2
- 235000012431 wafers Nutrition 0.000 description 65
- 239000010408 film Substances 0.000 description 33
- 239000013078 crystal Substances 0.000 description 30
- 239000002904 solvent Substances 0.000 description 23
- 239000000758 substrate Substances 0.000 description 13
- 239000010409 thin film Substances 0.000 description 13
- 238000007254 oxidation reaction Methods 0.000 description 11
- 230000003647 oxidation Effects 0.000 description 10
- 239000000463 material Substances 0.000 description 8
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 6
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 6
- WEVYAHXRMPXWCK-UHFFFAOYSA-N Acetonitrile Chemical compound CC#N WEVYAHXRMPXWCK-UHFFFAOYSA-N 0.000 description 6
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 description 6
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 description 6
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 6
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Chemical compound CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 description 6
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 6
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 description 6
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 6
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 6
- MTHSVFCYNBDYFN-UHFFFAOYSA-N diethylene glycol Chemical compound OCCOCCO MTHSVFCYNBDYFN-UHFFFAOYSA-N 0.000 description 6
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 description 6
- 238000006243 chemical reaction Methods 0.000 description 5
- HEDRZPFGACZZDS-UHFFFAOYSA-N Chloroform Chemical compound ClC(Cl)Cl HEDRZPFGACZZDS-UHFFFAOYSA-N 0.000 description 4
- RGSFGYAAUTVSQA-UHFFFAOYSA-N Cyclopentane Chemical compound C1CCCC1 RGSFGYAAUTVSQA-UHFFFAOYSA-N 0.000 description 4
- IAZDPXIOMUYVGZ-UHFFFAOYSA-N Dimethylsulphoxide Chemical compound CS(C)=O IAZDPXIOMUYVGZ-UHFFFAOYSA-N 0.000 description 4
- LRHPLDYGYMQRHN-UHFFFAOYSA-N N-Butanol Chemical compound CCCCO LRHPLDYGYMQRHN-UHFFFAOYSA-N 0.000 description 4
- OFBQJSOFQDEBGM-UHFFFAOYSA-N Pentane Chemical compound CCCCC OFBQJSOFQDEBGM-UHFFFAOYSA-N 0.000 description 4
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 description 4
- 230000008021 deposition Effects 0.000 description 4
- BDAGIHXWWSANSR-UHFFFAOYSA-N methanoic acid Natural products OC=O BDAGIHXWWSANSR-UHFFFAOYSA-N 0.000 description 4
- 239000002245 particle Substances 0.000 description 4
- 239000004065 semiconductor Substances 0.000 description 4
- 241000894007 species Species 0.000 description 4
- 239000000356 contaminant Substances 0.000 description 3
- 238000011109 contamination Methods 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 239000003921 oil Substances 0.000 description 3
- 235000019198 oils Nutrition 0.000 description 3
- 239000000377 silicon dioxide Substances 0.000 description 3
- 235000012239 silicon dioxide Nutrition 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- RYHBNJHYFVUHQT-UHFFFAOYSA-N 1,4-Dioxane Chemical compound C1COCCO1 RYHBNJHYFVUHQT-UHFFFAOYSA-N 0.000 description 2
- OSWFIVFLDKOXQC-UHFFFAOYSA-N 4-(3-methoxyphenyl)aniline Chemical compound COC1=CC=CC(C=2C=CC(N)=CC=2)=C1 OSWFIVFLDKOXQC-UHFFFAOYSA-N 0.000 description 2
- XDTMQSROBMDMFD-UHFFFAOYSA-N Cyclohexane Chemical compound C1CCCCC1 XDTMQSROBMDMFD-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- LDDQLRUQCUTJBB-UHFFFAOYSA-N ammonium fluoride Chemical compound [NH4+].[F-] LDDQLRUQCUTJBB-UHFFFAOYSA-N 0.000 description 2
- 230000003064 anti-oxidating effect Effects 0.000 description 2
- 239000012736 aqueous medium Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 239000008367 deionised water Substances 0.000 description 2
- 229910021641 deionized water Inorganic materials 0.000 description 2
- 229960004132 diethyl ether Drugs 0.000 description 2
- 238000000407 epitaxy Methods 0.000 description 2
- 230000005621 ferroelectricity Effects 0.000 description 2
- 230000005307 ferromagnetism Effects 0.000 description 2
- 235000019253 formic acid Nutrition 0.000 description 2
- DMEGYFMYUHOHGS-UHFFFAOYSA-N heptamethylene Natural products C1CCCCCC1 DMEGYFMYUHOHGS-UHFFFAOYSA-N 0.000 description 2
- 230000010354 integration Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- LYGJENNIWJXYER-UHFFFAOYSA-N nitromethane Chemical compound C[N+]([O-])=O LYGJENNIWJXYER-UHFFFAOYSA-N 0.000 description 2
- 238000005240 physical vapour deposition Methods 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- RUOJZAUFBMNUDX-UHFFFAOYSA-N propylene carbonate Chemical compound CC1COC(=O)O1 RUOJZAUFBMNUDX-UHFFFAOYSA-N 0.000 description 2
- 238000010926 purge Methods 0.000 description 2
- 238000000851 scanning transmission electron micrograph Methods 0.000 description 2
- 238000001350 scanning transmission electron microscopy Methods 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- XOJVVFBFDXDTEG-UHFFFAOYSA-N Norphytane Natural products CC(C)CCCC(C)CCCC(C)CCCC(C)C XOJVVFBFDXDTEG-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 239000010775 animal oil Substances 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 229910000420 cerium oxide Inorganic materials 0.000 description 1
- 238000001311 chemical methods and process Methods 0.000 description 1
- 239000012459 cleaning agent Substances 0.000 description 1
- 230000000593 degrading effect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 230000007717 exclusion Effects 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 230000002209 hydrophobic effect Effects 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 229910052743 krypton Inorganic materials 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000008204 material by function Substances 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910052754 neon Inorganic materials 0.000 description 1
- 229910052756 noble gas Inorganic materials 0.000 description 1
- 150000002835 noble gases Chemical class 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- BMMGVYCKOGBVEV-UHFFFAOYSA-N oxo(oxoceriooxy)cerium Chemical compound [Ce]=O.O=[Ce]=O BMMGVYCKOGBVEV-UHFFFAOYSA-N 0.000 description 1
- 238000005289 physical deposition Methods 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- 238000000527 sonication Methods 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 235000015112 vegetable and seed oil Nutrition 0.000 description 1
- 239000008158 vegetable oil Substances 0.000 description 1
- 229910052724 xenon Inorganic materials 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- 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
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/02—Pretreatment of the material to be coated
- C23C14/021—Cleaning or etching treatments
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- 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
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/02—Pretreatment of the material to be coated
- C23C14/024—Deposition of sublayers, e.g. to promote adhesion of the coating
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- 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
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/06—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the coating material
- C23C14/08—Oxides
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- 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
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/06—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the coating material
- C23C14/08—Oxides
- C23C14/083—Oxides of refractory metals or yttrium
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- 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
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
- C23C14/24—Vacuum evaporation
- C23C14/28—Vacuum evaporation by wave energy or particle radiation
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B23/00—Single-crystal growth by condensing evaporated or sublimed materials
- C30B23/02—Epitaxial-layer growth
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
- C30B29/10—Inorganic compounds or compositions
- C30B29/16—Oxides
- C30B29/22—Complex oxides
- C30B29/24—Complex oxides with formula AMeO3, wherein A is a rare earth metal and Me is Fe, Ga, Sc, Cr, Co or Al, e.g. ortho ferrites
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02104—Forming layers
- H01L21/02107—Forming insulating materials on a substrate
- H01L21/02109—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates
- H01L21/02112—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer
- H01L21/02172—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer the material containing at least one metal element, e.g. metal oxides, metal nitrides, metal oxynitrides or metal carbides
- H01L21/02175—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer the material containing at least one metal element, e.g. metal oxides, metal nitrides, metal oxynitrides or metal carbides characterised by the metal
- H01L21/02192—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer the material containing at least one metal element, e.g. metal oxides, metal nitrides, metal oxynitrides or metal carbides characterised by the metal the material containing at least one rare earth metal element, e.g. oxides of lanthanides, scandium or yttrium
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02104—Forming layers
- H01L21/02107—Forming insulating materials on a substrate
- H01L21/02225—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer
- H01L21/0226—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a deposition process
- H01L21/02263—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a deposition process deposition from the gas or vapour phase
- H01L21/02266—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a deposition process deposition from the gas or vapour phase deposition by physical ablation of a target, e.g. sputtering, reactive sputtering, physical vapour deposition or pulsed laser deposition
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02104—Forming layers
- H01L21/02107—Forming insulating materials on a substrate
- H01L21/02225—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer
- H01L21/0226—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a deposition process
- H01L21/02293—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a deposition process formation of epitaxial layers by a deposition process
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02104—Forming layers
- H01L21/02107—Forming insulating materials on a substrate
- H01L21/02296—Forming insulating materials on a substrate characterised by the treatment performed before or after the formation of the layer
- H01L21/02299—Forming insulating materials on a substrate characterised by the treatment performed before or after the formation of the layer pre-treatment
- H01L21/02304—Forming insulating materials on a substrate characterised by the treatment performed before or after the formation of the layer pre-treatment formation of intermediate layers, e.g. buffer layers, layers to improve adhesion, lattice match or diffusion barriers
Definitions
- the present invention relates, in general terms, to dysprosium scandate films and their methods of fabrication thereof.
- the present invention also relates to uses of dysprosium scandate film as a crystal growth platform on silicon. Background
- oxides used in photonics/electronics consist of two classes, amorphous layers on silicon or single crystal oxides with surface processing to delineate the device structures.
- the single crystal oxide layers have the advantage of increased functionality such as ferroelectricity, piezoelectricity and possibly ferromagnetism (for active devices).
- ferroelectricity ferroelectricity
- piezoelectricity piezoelectricity
- ferromagnetism for active devices.
- the growth of such layers on silicon is non-trivial.
- Dysprosium scandate (DSO) single crystal has a good lattice mismatch with the multifunctional perovskite oxides. It is an excellent substrate for growing high- quality thin films.
- DSO films there are still several challenges in integrating DSO films on silicon. Firstly, the surface of the silicon wafer gets oxidized very fast, which would severely affect subsequent epitaxial film growth. Secondly, a high- quality single crystallinity of DSO is required for the DSO film to act as a buffer layer.
- the present invention provides a method of fabricating a dysprosium scandate film on an etched surface of a silicon wafer immersed in an etchant, comprising: a) contacting the etched surface of the silicon wafer with an alcohol for at least 1 h in order to allow alkoxy moieties to be chemisorbed on the etched surface of the silicon wafer; b) depositing a Yttria-stabilized zirconia (YSZ) layer on the etched surface; c) depositing a CeC>2 layer on the YSZ layer; and d) depositing a dysprosium scandate (DSO) layer on the Ce02 layer.
- YSZ Yttria-stabilized zirconia
- reaction of alcohol with silicon can yield chemisorbed alkoxy species, which can help avoid the oxidation of the silicon wafer. Additionally, by keeping the surface of the wafers in contact with alcohol, the surface can be kept clean and unoxidized until its usage.
- the dysprosium scandate (DSO, DyScC ) layer can act as a platform for growing high-quality single-crystal thin films on silicon (including both p-type or n-type silicon).
- the etched surface is contacted with the alcohol within less than about 10 s after removal of the silicon wafer from the etchant.
- the alcohol is selected from methanol, ethanol, isopropanol and/or n-propanol.
- the alcohol has a purity of more than about 90%.
- the alcohol has a water content of less than about 1%. In some embodiments, the alcohol is purged with an inert gas.
- the alcohol is de-gassed.
- the etched surface on the silicon wafer is contacted with the alcohol under oxygen free conditions.
- the etched surface on the silicon wafer is contacted with the alcohol for about 1 h to about 24 h.
- the etched surface on the silicon wafer is contacted with the alcohol at a temperature of about 5 °C to about 50 °C.
- the method further comprises a step of cleaning the etched surface of the silicon wafer in order for the etched surface to be free of the etchant.
- the etchant is selected from Piranha solution, hydrofluoric acid, ammonia water, hydrogen peroxide and/or hydrochloric acid.
- the YSZ layer is deposited via pulsed laser deposition (PLD).
- PLD pulsed laser deposition
- the YSZ layer is deposited at a temperature of about 700 °C to about 800 °C.
- the YSZ layer is deposited at a pressure of about 10 6 Torr to about 10 5 Torr.
- the CeC>2 layer is deposited via pulsed laser deposition (PLD).
- PLD pulsed laser deposition
- the CeC>2 layer is deposited at a temperature of about 700 °C to about 800 °C.
- the CeC>2 layer is deposited at a pressure of about 10 6 Torr to about 10 5 Torr.
- the DSO layer is deposited via pulsed laser deposition (PLD).
- PLD pulsed laser deposition
- the DSO layer is deposited at a temperature of about 700 °C to about 800 °C.
- the DSO layer is deposited at a pressure of about 80 mTorr to about 150 mTorr.
- the DSO layer is characterised by a X-ray diffraction peak with a full width of half maximum (FWHM) value of about 0.22° to about 0.3°.
- FWHM full width of half maximum
- the present invention also provides a dysprosium scandate film, comprising: a) a silicon wafer; b) a Yttria-stabilized zirconia (YSZ) layer on the silicon wafer; c) a Ce02 layer on the YSZ layer; and d) a dysprosium scandate (DSO) layer on the Ce02 layer; wherein the DSO layer is characterised by a X-ray diffraction peak with a full width of half maximum (FWHM) value of about 0.220° to about 0.300°.
- a dysprosium scandate film comprising: a) a silicon wafer; b) a Yttria-stabilized zirconia (YSZ) layer on the silicon wafer; c) a Ce02 layer on the YSZ layer; and d) a dysprosium scandate (DSO) layer on the Ce02 layer; wherein the DSO layer is characterised by a X-ray diffraction peak with
- the DSO layer has an X-ray diffraction peak at about 22° to about 23°.
- the YSZ layer has a thickness of about 15 nm to about 40 nm.
- the CeC>2 layer has a thickness of about 30 nm to about 60 nm.
- the DSO layer has a thickness of about 15 nm to about 40 nm.
- the YSZ layer is a YSZ epitaxial layer.
- the CeC>2 layer is a CeC>2 epitaxial layer.
- the DSO layer is a DSO epitaxial layer.
- Figure 1 is a X-ray diffraction spectrum of Q-2Q scan of DSO based platform on silicon
- Figure 2 is a X-ray diffraction spectrum of the rocking curve of DSO based platform on silicon
- Figure 3 is an atom-resolution scanning transmission electron microscopy images of DSO based platform on silicon.
- the present invention is predicated on the understanding that avoiding or at least reducing the oxidation of silicon wafer before the pulsed laser deposition
- This method can be advantageous for epitaxial growth of crystalline layers on the silicon wafer. This method can be beneficial for obtaining a clean surface of silicon, for example, to achieve a better crystallinity of the grown film.
- the amorphous native silicon dioxide layer can be removed by buffered hydrofluoric acid, this amorphous oxidized layer will be formed again very soon if exposed to air even if only for a short duration.
- This re-oxidized layer is amorphous and not suitable for crystal film growth. It was found that after etching with hydrofluoric acid, the silicon wafers can be soaked immediately and immersed in methanol for several hours in order to maintain its pristine nature. Before deposition, the silicon wafer should not be exposed to the air and/or oxygen as much as possible.
- the present invention provides a method of preventing or reducing oxidation of an etched surface of a silicon wafer removed from an etchant, comprising: contacting the etched surface of the silicon wafer with an alcohol for at least 1 h in order to allow alkoxy moieties to be chemisorbed on the etched surface of the silicon wafer.
- the silicon wafer can have a (100) crystal plane or any other orientations.
- the reaction of alcohol with silicon can yield chemisorbed alkoxy species, which can help avoid the oxidation of silicon wafer. Additionally, by keeping the wafers in alcohol, the surface can be kept clean and unoxidized until its usage. Further, as the surface is saturated or at least covered with alkoxy moieties, the duration for handling the silicon wafer in an exposed environment can be increased without the adverse effect of oxidation.
- the etched surface is immersed in the alcohol. In other embodiments, the etched surface is completely immersed in the alcohol. In this regard, the etched surface and/or the silicon wafer can be submerged in the alcohol such that it is completely covered.
- the etched surface of the silicon wafer is contacted with an alcohol within less than about 10 s after removal of the silicon wafer from the etchant. In other embodiments, the etched surface on the silicon wafer is contacted with the alcohol within less than about 20 s after removal from the etchant. In other embodiments, the timing is less than about 18 s, about 16 s, about 14 s, about 12 s, about 8 s, about 6 s, about 5 s, about 4 s, about 3 s, about 2 s, or about 1 s.
- the alcohol is selected from methanol, ethanol, iso propanol and/or n-propanol. In other embodiments, the alcohol is methanol.
- the alcohol has a purity of more than about 90%. In other embodiments, the purity is more than about 91%, about 92%, about 93%, about 94%, about 95%, about 96%, about 97%, about 98%, about 99%, about 99.2%, about 99.4%, about 99.6%, or about 99.8%.
- the alcohol has a water content of less than about 1%. In other embodiments, the water content is less than about 0.9%, about 0.8%, about 0.7%, about 0.6%, about 0.5%, about 0.4%, about 0.3%, or about 0.2%.
- the alcohol is diluted with a solvent.
- the solvent is an aqueous medium.
- aqueous medium refers to a water based solvent or solvent system, and which comprises of mainly water.
- solvents can be either polar or non-polar, and/or either protic or aprotic.
- Solvent systems refer to combinations of solvents which resulting in a final single phase.
- Both 'solvents' and 'solvent systems' can include, and is not limited to, pentane, cyclopentane, hexane, cyclohexane, benzene, toluene, dioxane, chloroform, diethylether, dichloromethane, tetrahydrofuran, ethyl acetate, acetone, dimethylformamide, acetonitrile, dimethyl sulfoxide, nitromethane, propylene carbonate, formic acid, butanol, isopropanol, propanol, ethanol, methanol, acetic acid, ethylene glycol, diethylene glycol or water. Water based solvent or solvent systems can also include dissolved ions and salts.
- the solvent is an organic based solvent.
- Organic based solvents can be any carbon based solvents.
- Such solvents can be either polar or non-polar, and/or either protic or aprotic.
- Solvent systems refer to combinations of solvents which resulting in a final single phase.
- Both 'solvents' and 'solvent systems' can include, and is not limited to, pentane, cyclopentane, hexane, cyclohexane, benzene, toluene, dioxane, chloroform, diethylether, dichloromethane, tetrahydrofuran, ethyl acetate, acetone, dimethylformamide, acetonitrile, dimethyl sulfoxide, nitromethane, propylene carbonate, formic acid, butanol, isopropanol, propanol, ethanol, methanol, acetic acid, ethylene glycol, diethylene glycol or water.
- Organic based solvents or solvent systems can include, but not limited to, any non-polar liquid which can be hydrophobic and/or lipophilic. As such, oils such as animal oil, vegetable oil, petrochemical oil, and other synthetic oils are also included within this definition.
- the alcohol is diluted with a solvent such that its concentration is at least 50% of the solution.
- the alcohol is purged with an inert gas.
- An inert gas is a gas that does not undergo chemical reactions under a set of given conditions.
- noble gases such as He, Ne, Ar, Kr or Xe can be used.
- Inert gases can be used to avoid unwanted chemical reactions degrading a sample. These undesirable chemical reactions are often oxidation and hydrolysis reactions with the oxygen and moisture in air.
- oxygen can be displaced out from the alcohol.
- the alcohol is de-gassed.
- sonication can be used to de-gas the alcohol.
- a vacuum can be used to remove air and/or oxygen from the alcohol.
- the etched surface on the silicon wafer is contacted with the alcohol under oxygen free conditions.
- the contact step can be performed in a glove box.
- the contact step can be conducted under a curtain or flow of nitrogen gas. In such cases, the oxygen content in the environment is maintained at a minimum.
- the etched surface on the silicon wafer is contacted with the alcohol for at least about 1 h.
- the timing is at least about 2 h, about 3 h, about 4 h, about 5 h, about 6 h, about 7 h, about 8 h, about 10 h, about 12 h, about 14 h, about 16 h, about 18 h, about 20 h, about 22 h, or about 24 h.
- the etched surface on the silicon wafer is contacted with the alcohol for about 1 h to about 24 h. In other embodiments, the timing is about 1 h to about 22 h, about 1 h to about 20 h, about 1 h to about 18 h, about
- the etched surface on the silicon wafer is contacted with the alcohol at a temperature of about 5 °C to about 50 °C. In other embodiments, the temperature is about 5 °C to about 45 °C, about 5 °C to about 40 °C, about 5 °C to about 35 °C, about 5 °C to about 30 °C, or about 5 °C to about 25 °C.
- the method further comprises a step of cleaning the etched surface of the silicon wafer in order for the etched surface to be free of the etchant. This can for example be performed using a blow gun or wiping the etched surface using an appropriate cleaning agent.
- the etchant is selected from Piranha solution, hydrofluoric acid ammonia water, hydrogen peroxide and/or hydrochloric acid.
- RCA clean can be used, which is a standard set of wafer cleaning steps which need to be performed before high-temperature processing steps (oxidation, diffusion, CVD) of silicon wafers in semiconductor manufacturing. It involves the following chemical processes performed in sequence: i) Removal of the organic contaminants (SC-1; organic clean + particle clean)
- the first step is performed with a solution of (ratios may vary):
- the optional second step is a short immersion in a 1: 100 or 1:50 solution of aqueous HF (hydrofluoric acid) at 25 °C for about fifteen seconds, in order to remove the thin oxide layer and some fraction of ionic contaminants. If this step is performed without ultra high purity materials and ultra clean containers, it can lead to recontamination since the bare silicon surface is very reactive. In any case, the subsequent step (SC-2) dissolves and regrows the oxide layer. iii) Removal of ionic contamination (SC-2; ionic clean)
- SC-2 The third and last step (called SC-2) is performed with a solution of (ratios may vary):
- the Si substrate as treated herein can be exposed to air for at least about 10 min. In comparison, the etched Si without alcohol treatment cannot be used because of the re-oxidized layer.
- the etched surface By maintaining the non-oxidised state of the etched surface of the silicon wafer, the etched surface can be used for epitaxial growth of single crystals whenever it is required. As the etched surface can be stored for a greater period of time using this method, greater flexibility in the production of semiconductors can be expected.
- Single crystal oxide layers can have the advantages of increased functionality such as ferroelectricity, piezoelectricity, and possibly ferromagnetism (for active devices). However, the growth of such layers on silicon is non-trivial.
- the present invention also relates to single crystal oxide layers formed on the etched surface on the silicon wafer and methods of fabrication thereof.
- the single crystal films provide a platform for integrating multifunctional oxide materials onto silicon platform used in the semiconductor industry useful for designing various high-performance devices.
- SrRuC is not an insulator, which will severely affect the electrical property and applications of the film deposited on it.
- SrRuC is not a widely used substrate for oxide thin film as surface treatment procedures to accomplish atomically flat surfaces with single terminating layer for various metal oxide substrates is not straightforward.
- the present invention provides a method of fabricating a dysprosium scandate film on an etched surface of a silicon wafer immersed in an etchant, comprising: a) contacting the etched surface of the silicon wafer with an alcohol for at least 1 h in order to allow alkoxy moieties to be chemisorbed on the etched surface of the silicon wafer; b) depositing a Yttria-stabilized zirconia (YSZ) layer on the etched surface;
- YSZ Yttria-stabilized zirconia
- the etched surface of the silicon wafer is protected by alkoxy, single crystals films with low defects can be formed on the silicon wafer.
- the dysprosium scandate (DSO, DyScOs) layer can act as a platform for growing high-quality singlecrystal thin films on silicon (including both p-type or n-type silicon).
- amorphous or polycrystal DSO film cannot be grown directly on Si; only amorphous or polycrystal DSO film can grow on Si substrate due to the lattice mismatch.
- amorphous or polycrystal films When determined using X-ray diffraction, amorphous or polycrystal films have peaks with a full width of half maximum (FWHM) much larger than 1°, or in other cases the FWHM value is unobtainable as the peak is too broad.
- FWHM full width of half maximum
- the method of fabricating a dysprosium scandate film is on an etched surface of a silicon wafer, the silicon wafer having been previously immersed in an etchant and is removed from the etchant in order for the dysprosium scandate film to form on the etched surface. Accordingly, the method is a method of fabricating a dysprosium scandate film on an etched surface of a silicon wafer (removed from an etchant).
- the method of fabricating a dysprosium scandate film on an etched surface of a silicon wafer comprises a step before step a) of providing a silicon wafer which has been etched by an etchant.
- the etchant can be selected from Piranha solution, hydrofluoric acid ammonia water, hydrogen peroxide and/or hydrochloric acid.
- the YSZ layer is deposited via pulsed laser deposition (PLD).
- Pulsed laser deposition is a physical vapor deposition (PVD) technique where a high-power pulsed laser beam is focused inside a vacuum chamber to strike a target of the material that is to be deposited. This material is vaporized from the target (in a plasma plume) which deposits it as a thin film on a substrate (such as a silicon wafer facing the target). This process can occur in ultra high vacuum or in the presence of a background gas, such as oxygen which is commonly used when depositing oxides to fully oxygenate the deposited films.
- a background gas such as oxygen which is commonly used when depositing oxides to fully oxygenate the deposited films.
- the YSZ layer is deposited at a temperature of about 700 °C to about 800 °C. In other embodiments, the temperature is about 700 °C to about 780 °C, about 700 °C to about 760 °C, about 700 °C to about 740 °C, or about 700 °C to about 720 °C.
- the YSZ layer is deposited at a pressure of about 10 7 Torr to about 10 4 Torr, or about 10 6 Torr to about 10 5 Torr.
- the CeC>2 layer is deposited via pulsed laser deposition (PLD).
- PLD pulsed laser deposition
- the CeC>2 layer is deposited at a temperature of about 700 °C to about 800 °C. In other embodiments, the temperature is about 700 °C to about 780 °C, about 700 °C to about 760 °C, about 700 °C to about 740 °C, or about 700 °C to about 720 °C.
- the CeC>2 layer is deposited at a pressure of about 10 7 Torr to about 10 4 Torr, or about 10 6 Torr to about 10 5 Torr.
- the DSO layer is deposited via pulsed laser deposition (PLD).
- PLD pulsed laser deposition
- the DSO layer is deposited at a temperature of about 700 °C to about 800 °C. In other embodiments, the temperature is about 700 °C to about 780 °C, about 700 °C to about 760 °C, about 700 °C to about 740 °C, or about 700 °C to about 720 °C.
- the DSO layer is deposited at a pressure of about 80 mTorr to about 150 mTorr. In other embodiments, the pressure is about 80 mTorr to about 140 mTorr, about 80 mTorr to about 130 mTorr, about 80 mTorr to about 120 mTorr, about 80 mTorr to about 110 mTorr, or about 80 mTorr to about 100 mTorr.
- Yttria-stabilized zirconia (YSZ) layer can be first deposited on silicon at high vacuum and 720 °C by pulsed laser deposition (PLD). This approach is very effective in removing any extra silicon dioxide. Subsequently, CeC>2 can be deposited on YSZ under the same vacuum condition and temperature to provide a beneficial chemical buffer layer between YSZ and oxide thin film (like DSO) and also to overcome the lattice mismatch between them. Finally, DSO can be deposited on the YSZ/Ce02 layer at 100 mTorr and 720 °C. The X-ray diffraction (XRD) spectra confirmed the epitaxial growth of DySc03, as shown in Figure 1.
- PLD pulsed laser deposition
- the present invention also provides a dysprosium scandate film, comprising: a) a silicon wafer; b) a Yttria-stabilized zirconia (YSZ) layer on the silicon wafer; c) a Ce02 layer on the YSZ layer; and d) a dysprosium scandate (DSO) layer on the Ce02 layer; wherein the DSO layer has an X-ray diffraction peak with a full width of half maximum (FWHM) value of about 0.220° to about 0.300°.
- a dysprosium scandate film comprising: a) a silicon wafer; b) a Yttria-stabilized zirconia (YSZ) layer on the silicon wafer; c) a Ce02 layer on the YSZ layer; and d) a dysprosium scandate (DSO) layer on the Ce02 layer; wherein the DSO layer has an X-ray diffraction peak with a full width of half maximum
- single crystals with low defects can be grown or deposited on its etched surface.
- the DSO layer has an X-ray diffraction peak at about 22° to about 23°. In other embodiments, the X-ray diffraction peak at about 22° to about 22.9°, about 22° to about 22.8°, about 22° to about 22.7°, about 22° to about 22.6°, about 22° to about 22.5°, about 22° to about 22.4°, about 22° to about 22.3°, about 22° to about 22.2°, or about 22.1° to about 22.2°.
- the DSO layer has an X-ray diffraction peak with a full width of half maximum (FWHM) value of about 0.230° to about 0.300°, about 0.240° to about 0.300°, about 0.250° to about 0.300°, about 0.260° to about 0.300°, about 0.270° to about 0.300°, or about 0.280° to about 0.300°.
- the FWHM is about 0.230° to about 0.290°, about 0.240° to about 0.290°, or about 0.240° to about 0.280°.
- the YSZ layer has a thickness of about 15 nm to about 40 nm. In other embodiments, the thickness is about 15 nm to about 38 nm, about 15 nm to about 36 nm, about 15 nm to about 34 nm, about 15 nm to about 32 nm, about 15 nm to about 30 nm, about 16 nm to about 30 nm, about 18 nm to about 30 nm, about 20 nm to about 30 nm, about 22 nm to about 30 nm, about 24 nm to about 30 nm, or about 26 nm to about 30 nm.
- the CeC>2 layer has a thickness of about 30 nm to about 60 nm. In other embodiments, the thickness is about 30 nm to about 58 nm, about 30 nm to about 56 nm, about 30 nm to about 54 nm, about 30 nm to about 52 nm, about 30 nm to about 50 nm, about 32 nm to about 50 nm, about 34 nm to about 50 nm, about 36 nm to about 50 nm, about 38 nm to about 50 nm, about 40 nm to about 50 nm, about 40 nm to about 48 nm, about 40 nm to about 46 nm, or about 40 nm to about 44 nm.
- the DSO layer has a thickness of about 15 nm to about 40 nm. In other embodiments, the thickness is about 15 nm to about 38 nm, about 15 nm to about 36 nm, about 15 nm to about 34 nm, about 15 nm to about 32 nm, about 15 nm to about 30 nm, about 16 nm to about 30 nm, about
- 16 18 nm to about 30 nm, about 20 nm to about 30 nm, about 20 nm to about 28 nm, about 20 nm to about 26 nm, about 20 nm to about 24 nm, or about 20 nm to about 22 nm.
- the YSZ layer is a YSZ epitaxial layer.
- Epitaxy refers to a type of crystal growth or material deposition in which new crystalline layers are formed with one or more well-defined orientations with respect to the crystalline substrate.
- the deposited crystalline film is called an epitaxial film or epitaxial layer.
- the relative orientation(s) of the epitaxial layer to the crystalline substrate is defined in terms of the orientation of the crystal lattice of each material.
- the new layer For epitaxial growth, the new layer must be crystalline and each crystallographic domain of the overlayer must have a well-defined orientation relative to the substrate crystal structure. Amorphous growth or multicrystalline growth with random crystal orientation does not meet this criterion.
- the crystal orientation of YSZ layer is [001].
- the CeC>2 layer is a CeC>2 epitaxial layer. In some embodiments, the crystal orientation of CeC>2 layer is [001].
- the DSO layer is a DSO epitaxial layer. In some embodiments, the crystal orientation of DSO layer is [001].
- the X-ray diffraction rocking curve of DySc03 has a full width of half maximum (FWHM) value of 0.285°, as shown in Figure 2, which shows an excellent crystallinity.
- FWHM full width of half maximum
- the atom-resolution scanning transmission electron microscopy (STEM) images of DSO buffer layers show a distinct contrast among different buffer layers of DSO/Ce0 2 /YSZ.
- the epitaxy relationship is well maintained in the Ce0 2 /YSZ buffered layer case, but there is a small off tilt between DSO and Ce02,
- the high-quality single-crystal DSO thin film grown on silicon was achieved.
- the FWHM value of the DSO is about 0.285° (fitting using Matlab), which is very good as a buffer layer.
- the high-resolution STEM images also confirmed the epitaxial growth mode and good crystallinity of DSO film.
- the DSO layer will provide a platform for depositing functional materials and further the device design. This platform allows for integration of innumerable multifunctional oxide materials into a silicon platform used in the semiconductor industry for designing various high-performance devices, such as an ultrahigh-speed optical modulator.
- the DSO layer is characterised by a X-ray diffraction peak with a FWHM value of about 0.2° to about 0.4°, about 0.2° to about 0.3.8°, about 0.2° to about 0.36°, about 0.2° to about 0.34°, about 0.2° to about 0.32°, about 0.2° to about 0.3°, about 0.22° to about 0.3°, about 0.24° to about 0.3°, about 0.26° to about 0.3°, or about 0.28° to about 0.3°.
- FWHM full width half maximum
- the method of fabricating a dysprosium scandate film on an etched surface of a silicon wafer removed from an etchant comprises: a) contacting the etched surface of the silicon wafer with an alcohol for at least 1 h in order to allow alkoxy moieties to be chemisorbed on the etched surface of the silicon wafer; b) depositing a Yttria-stabilized zirconia (YSZ) layer on the etched surface;
- YSZ Yttria-stabilized zirconia
- the integration of DSO onto a silicon wafer provides a platform for depositing innumerable multifunctional oxide materials on silicon wafers for designing various high-performance devices because a DSO single crystal can be a good substrate for epitaxial films. Additionally, because of the low oxidation state of the etched surface of the silicon wafer, a high quality of the buffer layers can be obtained. It is thus much easier to deposit high-quality epitaxial films when the quality of the buffer layers is high.
- the method preventing and/or reducing oxidation of silicon wafer provides an epitaxial growth template for the growth of oxide thin films using a physical deposition technique, which is crucial for growing high-quality DSO films.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Metallurgy (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Computer Hardware Design (AREA)
- Power Engineering (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Manufacturing & Machinery (AREA)
- General Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- Crystallography & Structural Chemistry (AREA)
- Optics & Photonics (AREA)
- Health & Medical Sciences (AREA)
- Toxicology (AREA)
- Inorganic Chemistry (AREA)
- Crystals, And After-Treatments Of Crystals (AREA)
Abstract
5 This disclosure concerns a method of fabricating a dysprosium scandate film on an etched surface of a silicon wafer removed from an etchant, comprising contacting the etched surface of the silicon wafer with an alcohol for at least 1 h in order to allow alkoxy moieties to be chemisorbed on the etched surface of the silicon wafer; depositing a Yttria-stabilized zirconia (YSZ) layer on the 10 etched surface; depositing a CeO2 layer on the YSZ layer; and depositing a dysprosium scandate (DSO) layer on the CeO2 layer.
Description
DYSPROSIUM SCANDATE FILMS, METHODS OF FABRICATION
AND USES THEREOF
Technical Field
The present invention relates, in general terms, to dysprosium scandate films and their methods of fabrication thereof. The present invention also relates to uses of dysprosium scandate film as a crystal growth platform on silicon. Background
Most oxides used in photonics/electronics consist of two classes, amorphous layers on silicon or single crystal oxides with surface processing to delineate the device structures. The single crystal oxide layers have the advantage of increased functionality such as ferroelectricity, piezoelectricity and possibly ferromagnetism (for active devices). However, the growth of such layers on silicon is non-trivial.
Dysprosium scandate (DSO) single crystal has a good lattice mismatch with the multifunctional perovskite oxides. It is an excellent substrate for growing high- quality thin films. However, there are still several challenges in integrating DSO films on silicon. Firstly, the surface of the silicon wafer gets oxidized very fast, which would severely affect subsequent epitaxial film growth. Secondly, a high- quality single crystallinity of DSO is required for the DSO film to act as a buffer layer.
It would be desirable to overcome or ameliorate at least one of the above- described problems. Summary
The present invention is predicated on the understanding that the growth and/or
1
deposition of high-quality single-crystal DSO, CeC>2 (Cerium Oxide) and YSZ (yttria-stabilized zirconia) thin films on a substrate is dependent on the structural and chemical properties of the substrate. Accordingly, by carefully controlling the chemical state of the substrate, physical properties of the single crystal thin films can be altered.
Accordingly, the present invention provides a method of fabricating a dysprosium scandate film on an etched surface of a silicon wafer immersed in an etchant, comprising: a) contacting the etched surface of the silicon wafer with an alcohol for at least 1 h in order to allow alkoxy moieties to be chemisorbed on the etched surface of the silicon wafer; b) depositing a Yttria-stabilized zirconia (YSZ) layer on the etched surface; c) depositing a CeC>2 layer on the YSZ layer; and d) depositing a dysprosium scandate (DSO) layer on the Ce02 layer.
Advantageously, it was found that the reaction of alcohol with silicon can yield chemisorbed alkoxy species, which can help avoid the oxidation of the silicon wafer. Additionally, by keeping the surface of the wafers in contact with alcohol, the surface can be kept clean and unoxidized until its usage.
Advantageously, the dysprosium scandate (DSO, DyScC ) layer can act as a platform for growing high-quality single-crystal thin films on silicon (including both p-type or n-type silicon).
In some embodiments, the etched surface is contacted with the alcohol within less than about 10 s after removal of the silicon wafer from the etchant.
In some embodiments, the alcohol is selected from methanol, ethanol, isopropanol and/or n-propanol.
In some embodiments, the alcohol has a purity of more than about 90%.
2
In some embodiments, the alcohol has a water content of less than about 1%. In some embodiments, the alcohol is purged with an inert gas.
In some embodiments, the alcohol is de-gassed.
In some embodiments, the etched surface on the silicon wafer is contacted with the alcohol under oxygen free conditions.
In some embodiments, the etched surface on the silicon wafer is contacted with the alcohol for about 1 h to about 24 h.
In some embodiments, the etched surface on the silicon wafer is contacted with the alcohol at a temperature of about 5 °C to about 50 °C.
In some embodiments, the method further comprises a step of cleaning the etched surface of the silicon wafer in order for the etched surface to be free of the etchant.
In some embodiments, the etchant is selected from Piranha solution, hydrofluoric acid, ammonia water, hydrogen peroxide and/or hydrochloric acid.
In some embodiments, the YSZ layer is deposited via pulsed laser deposition (PLD).
In some embodiments, the YSZ layer is deposited at a temperature of about 700 °C to about 800 °C.
In some embodiments, the YSZ layer is deposited at a pressure of about 10 6 Torr to about 10 5 Torr.
3
In some embodiments, the CeC>2 layer is deposited via pulsed laser deposition (PLD).
In some embodiments, the CeC>2 layer is deposited at a temperature of about 700 °C to about 800 °C.
In some embodiments, the CeC>2 layer is deposited at a pressure of about 10 6 Torr to about 10 5 Torr.
In some embodiments, the DSO layer is deposited via pulsed laser deposition (PLD).
In some embodiments, the DSO layer is deposited at a temperature of about 700 °C to about 800 °C.
In some embodiments, the DSO layer is deposited at a pressure of about 80 mTorr to about 150 mTorr.
In some embodiments, the DSO layer is characterised by a X-ray diffraction peak with a full width of half maximum (FWHM) value of about 0.22° to about 0.3°.
The present invention also provides a dysprosium scandate film, comprising: a) a silicon wafer; b) a Yttria-stabilized zirconia (YSZ) layer on the silicon wafer; c) a Ce02 layer on the YSZ layer; and d) a dysprosium scandate (DSO) layer on the Ce02 layer; wherein the DSO layer is characterised by a X-ray diffraction peak with a full width of half maximum (FWHM) value of about 0.220° to about 0.300°.
In some embodiments, the DSO layer has an X-ray diffraction peak at about 22° to about 23°.
4
In some embodiments, the YSZ layer has a thickness of about 15 nm to about 40 nm.
In some embodiments, the CeC>2 layer has a thickness of about 30 nm to about 60 nm.
In some embodiments, the DSO layer has a thickness of about 15 nm to about 40 nm.
In some embodiments, the YSZ layer is a YSZ epitaxial layer.
In some embodiments, the CeC>2 layer is a CeC>2 epitaxial layer.
In some embodiments, the DSO layer is a DSO epitaxial layer.
Brief description of the drawings
Embodiments of the present invention will now be described, by way of nonlimiting example, with reference to the drawings in which:
Figure 1 is a X-ray diffraction spectrum of Q-2Q scan of DSO based platform on silicon;
Figure 2 is a X-ray diffraction spectrum of the rocking curve of DSO based platform on silicon; and
Figure 3 is an atom-resolution scanning transmission electron microscopy images of DSO based platform on silicon.
Detailed description
The present invention is predicated on the understanding that avoiding or at least reducing the oxidation of silicon wafer before the pulsed laser deposition
5
can be advantageous for epitaxial growth of crystalline layers on the silicon wafer. This method can be beneficial for obtaining a clean surface of silicon, for example, to achieve a better crystallinity of the grown film.
Although the amorphous native silicon dioxide layer can be removed by buffered hydrofluoric acid, this amorphous oxidized layer will be formed again very soon if exposed to air even if only for a short duration. This re-oxidized layer is amorphous and not suitable for crystal film growth. It was found that after etching with hydrofluoric acid, the silicon wafers can be soaked immediately and immersed in methanol for several hours in order to maintain its pristine nature. Before deposition, the silicon wafer should not be exposed to the air and/or oxygen as much as possible.
Accordingly, the present invention provides a method of preventing or reducing oxidation of an etched surface of a silicon wafer removed from an etchant, comprising: contacting the etched surface of the silicon wafer with an alcohol for at least 1 h in order to allow alkoxy moieties to be chemisorbed on the etched surface of the silicon wafer.
The silicon wafer can have a (100) crystal plane or any other orientations.
Advantageously, it was found that the reaction of alcohol with silicon can yield chemisorbed alkoxy species, which can help avoid the oxidation of silicon wafer. Additionally, by keeping the wafers in alcohol, the surface can be kept clean and unoxidized until its usage. Further, as the surface is saturated or at least covered with alkoxy moieties, the duration for handling the silicon wafer in an exposed environment can be increased without the adverse effect of oxidation.
Without wanting to be bound by theory, it is believed that soaking the silicon wafer in alcohol can play a role of anti-oxidation in that the silicon will react with methanol at room temperature, and this yields a chemisorbed alkoxy species
6
with negligible oxidation occurring. The alkoxy species will disappear or be removed when exposed to a high temperature and thus will not affect film deposition. This anti-oxidation technique of silicon wafer is advantageously low- cost and highly efficient.
In some embodiments, the etched surface is immersed in the alcohol. In other embodiments, the etched surface is completely immersed in the alcohol. In this regard, the etched surface and/or the silicon wafer can be submerged in the alcohol such that it is completely covered.
In some embodiments, the etched surface of the silicon wafer is contacted with an alcohol within less than about 10 s after removal of the silicon wafer from the etchant. In other embodiments, the etched surface on the silicon wafer is contacted with the alcohol within less than about 20 s after removal from the etchant. In other embodiments, the timing is less than about 18 s, about 16 s, about 14 s, about 12 s, about 8 s, about 6 s, about 5 s, about 4 s, about 3 s, about 2 s, or about 1 s.
It was found that the re-oxidized layer will form immediately after the exposure of Si to the air. Thus, growth of films on Si can be improved by reducing the time of exposure to air. Advantageously, by quickly transferring the etched surface of the silicon wafer from the etchant to the alcohol, the exposure to air and hence oxygen is minimised.
In some embodiments, the alcohol is selected from methanol, ethanol, iso propanol and/or n-propanol. In other embodiments, the alcohol is methanol.
In some embodiments, the alcohol has a purity of more than about 90%. In other embodiments, the purity is more than about 91%, about 92%, about 93%, about 94%, about 95%, about 96%, about 97%, about 98%, about 99%, about 99.2%, about 99.4%, about 99.6%, or about 99.8%.
7
In some embodiments, the alcohol has a water content of less than about 1%. In other embodiments, the water content is less than about 0.9%, about 0.8%, about 0.7%, about 0.6%, about 0.5%, about 0.4%, about 0.3%, or about 0.2%.
In some embodiments, the alcohol is diluted with a solvent. In some embodiments, the solvent is an aqueous medium. The term 'aqueous medium' used herein refers to a water based solvent or solvent system, and which comprises of mainly water. Such solvents can be either polar or non-polar, and/or either protic or aprotic. Solvent systems refer to combinations of solvents which resulting in a final single phase. Both 'solvents' and 'solvent systems' can include, and is not limited to, pentane, cyclopentane, hexane, cyclohexane, benzene, toluene, dioxane, chloroform, diethylether, dichloromethane, tetrahydrofuran, ethyl acetate, acetone, dimethylformamide, acetonitrile, dimethyl sulfoxide, nitromethane, propylene carbonate, formic acid, butanol, isopropanol, propanol, ethanol, methanol, acetic acid, ethylene glycol, diethylene glycol or water. Water based solvent or solvent systems can also include dissolved ions and salts.
In other embodiments, the solvent is an organic based solvent. Organic based solvents can be any carbon based solvents. Such solvents can be either polar or non-polar, and/or either protic or aprotic. Solvent systems refer to combinations of solvents which resulting in a final single phase. Both 'solvents' and 'solvent systems' can include, and is not limited to, pentane, cyclopentane, hexane, cyclohexane, benzene, toluene, dioxane, chloroform, diethylether, dichloromethane, tetrahydrofuran, ethyl acetate, acetone, dimethylformamide, acetonitrile, dimethyl sulfoxide, nitromethane, propylene carbonate, formic acid, butanol, isopropanol, propanol, ethanol, methanol, acetic acid, ethylene glycol, diethylene glycol or water. Organic based solvents or solvent systems can include, but not limited to, any non-polar liquid which can be hydrophobic and/or lipophilic. As such, oils such as animal oil, vegetable oil, petrochemical oil, and other synthetic oils are also included within this definition.
8
In some embodiments, the alcohol is diluted with a solvent such that its concentration is at least 50% of the solution.
In some embodiments, the alcohol is purged with an inert gas. An inert gas is a gas that does not undergo chemical reactions under a set of given conditions. For example, noble gases such as He, Ne, Ar, Kr or Xe can be used. Inert gases can be used to avoid unwanted chemical reactions degrading a sample. These undesirable chemical reactions are often oxidation and hydrolysis reactions with the oxygen and moisture in air. By purging with an inert gas, oxygen can be displaced out from the alcohol.
In some embodiments, the alcohol is de-gassed. For example, sonication can be used to de-gas the alcohol. Alternatively, a vacuum can be used to remove air and/or oxygen from the alcohol.
Additionally, purging the Si surface or maintaining the Si wafer in an inert environment further reduce the re-oxidation of the Si layer. In some embodiments, the etched surface on the silicon wafer is contacted with the alcohol under oxygen free conditions. For example, the contact step can be performed in a glove box. Alternatively, the contact step can be conducted under a curtain or flow of nitrogen gas. In such cases, the oxygen content in the environment is maintained at a minimum.
In some embodiments, the etched surface on the silicon wafer is contacted with the alcohol for at least about 1 h. In other embodiments, the timing is at least about 2 h, about 3 h, about 4 h, about 5 h, about 6 h, about 7 h, about 8 h, about 10 h, about 12 h, about 14 h, about 16 h, about 18 h, about 20 h, about 22 h, or about 24 h.
In some embodiments, the etched surface on the silicon wafer is contacted with the alcohol for about 1 h to about 24 h. In other embodiments, the timing is about 1 h to about 22 h, about 1 h to about 20 h, about 1 h to about 18 h, about
9
1 h to about 16 h, about 1 h to about 14 h, about 1 h to about 12 h, about 1 h to about 10 h, about 1 h to about 8 h, about 1 h to about 6 h, about 1 h to about 5 h, about 1 h to about 4 h, about 1 h to about 3 h, or about 1 h to about
2 h.
In some embodiments, the etched surface on the silicon wafer is contacted with the alcohol at a temperature of about 5 °C to about 50 °C. In other embodiments, the temperature is about 5 °C to about 45 °C, about 5 °C to about 40 °C, about 5 °C to about 35 °C, about 5 °C to about 30 °C, or about 5 °C to about 25 °C.
In some embodiments, the method further comprises a step of cleaning the etched surface of the silicon wafer in order for the etched surface to be free of the etchant. This can for example be performed using a blow gun or wiping the etched surface using an appropriate cleaning agent.
In some embodiments, the etchant is selected from Piranha solution, hydrofluoric acid ammonia water, hydrogen peroxide and/or hydrochloric acid.
For example, RCA clean can be used, which is a standard set of wafer cleaning steps which need to be performed before high-temperature processing steps (oxidation, diffusion, CVD) of silicon wafers in semiconductor manufacturing. It involves the following chemical processes performed in sequence: i) Removal of the organic contaminants (SC-1; organic clean + particle clean)
The first step is performed with a solution of (ratios may vary):
5 parts of deionized water
1 part of ammonia water, (29% by weight of Nhb)
1 part of aqueous H2O2 (hydrogen peroxide, 30%) at 75 or 80 °C typically for 10 minutes. This base-peroxide mixture removes organic residues. Particles are also very effectively removed, even insoluble particles, since SC-1 modifies the surface and particle zeta potentials and causes
10
them to repel. This treatment results in the formation of a thin silicon dioxide layer (about 10 Angstrom) on the silicon surface, along with a certain degree of metallic contamination (notably iron) that will be removed in subsequent steps. ii) Removal of thin oxide layer (oxide strip, optional)
The optional second step (for bare silicon wafers) is a short immersion in a 1: 100 or 1:50 solution of aqueous HF (hydrofluoric acid) at 25 °C for about fifteen seconds, in order to remove the thin oxide layer and some fraction of ionic contaminants. If this step is performed without ultra high purity materials and ultra clean containers, it can lead to recontamination since the bare silicon surface is very reactive. In any case, the subsequent step (SC-2) dissolves and regrows the oxide layer. iii) Removal of ionic contamination (SC-2; ionic clean)
The third and last step (called SC-2) is performed with a solution of (ratios may vary):
6 parts of deionized water
1 part of aqueous HCI (hydrochloric acid, 37% by weight)
1 part of aqueous H2O2 (hydrogen peroxide, 30%) at 75 or 80 °C, typically for 10 minutes. This treatment effectively removes the remaining traces of metallic (ionic) contaminants, some of which were introduced in the SC-1 cleaning step. It also leaves a thin passivating layer on the wafer surface, which protects the surface from subsequent contamination (bare exposed silicon is contaminated immediately).
The Si substrate as treated herein can be exposed to air for at least about 10 min. In comparison, the etched Si without alcohol treatment cannot be used because of the re-oxidized layer.
By maintaining the non-oxidised state of the etched surface of the silicon wafer, the etched surface can be used for epitaxial growth of single crystals whenever it is required. As the etched surface can be stored for a greater period of time using this method, greater flexibility in the production of semiconductors can be expected.
11
Single crystal oxide layers can have the advantages of increased functionality such as ferroelectricity, piezoelectricity, and possibly ferromagnetism (for active devices). However, the growth of such layers on silicon is non-trivial.
In another aspect, the present invention also relates to single crystal oxide layers formed on the etched surface on the silicon wafer and methods of fabrication thereof. The single crystal films provide a platform for integrating multifunctional oxide materials onto silicon platform used in the semiconductor industry useful for designing various high-performance devices.
This is predicated on the understanding that current single crystal oxides and/or its production thereof cannot meet the requirements in a commercial setting. For example, complex oxides such as Lao.67Sro.33MnC>3 can be grown on silicon using CeC>2 and Yttria-stabilized zirconia (YSZ) as buffer layers. However, this is insufficient as there can be a large lattice mismatch between CeC>2 and the perovskite oxides. Epitaxial growth will be poor and the crystallinity of the thin film is not good. A prior solution involves using SrRuC as an additional buffer layer and epitaxial template to deposit Lao.67Sro.33MnC>3. However, there are two issues of using SrRuC buffer layer. Firstly, SrRuC is not an insulator, which will severely affect the electrical property and applications of the film deposited on it. Secondly, SrRuC is not a widely used substrate for oxide thin film as surface treatment procedures to accomplish atomically flat surfaces with single terminating layer for various metal oxide substrates is not straightforward.
Accordingly, the present invention provides a method of fabricating a dysprosium scandate film on an etched surface of a silicon wafer immersed in an etchant, comprising: a) contacting the etched surface of the silicon wafer with an alcohol for at least 1 h in order to allow alkoxy moieties to be chemisorbed on the etched surface of the silicon wafer; b) depositing a Yttria-stabilized zirconia (YSZ) layer on the etched surface;
12
c) depositing a CeC>2 layer on the YSZ layer; and d) depositing a dysprosium scandate (DSO) layer on the CeC>2 layer.
Advantageously, as the etched surface of the silicon wafer is protected by alkoxy, single crystals films with low defects can be formed on the silicon wafer. By protecting the etched surface with chemisorbed alkoxy moieties, the handling time of the silicon wafer can be increased. The dysprosium scandate (DSO, DyScOs) layer can act as a platform for growing high-quality singlecrystal thin films on silicon (including both p-type or n-type silicon).
In contrast, single crystal DSO film cannot be grown directly on Si; only amorphous or polycrystal DSO film can grow on Si substrate due to the lattice mismatch. When determined using X-ray diffraction, amorphous or polycrystal films have peaks with a full width of half maximum (FWHM) much larger than 1°, or in other cases the FWHM value is unobtainable as the peak is too broad. In this regard, the inventors have found that by gradually and specifically tuning the crystal lattice, a DSO platform with a suitable crystallinity can be formed.
It would be clear to the skilled person that the method of fabricating a dysprosium scandate film is on an etched surface of a silicon wafer, the silicon wafer having been previously immersed in an etchant and is removed from the etchant in order for the dysprosium scandate film to form on the etched surface. Accordingly, the method is a method of fabricating a dysprosium scandate film on an etched surface of a silicon wafer (removed from an etchant).
In some embodiments, the method of fabricating a dysprosium scandate film on an etched surface of a silicon wafer comprises a step before step a) of providing a silicon wafer which has been etched by an etchant. The etchant can be selected from Piranha solution, hydrofluoric acid ammonia water, hydrogen peroxide and/or hydrochloric acid.
13
In some embodiments, the YSZ layer is deposited via pulsed laser deposition (PLD). Pulsed laser deposition (PLD) is a physical vapor deposition (PVD) technique where a high-power pulsed laser beam is focused inside a vacuum chamber to strike a target of the material that is to be deposited. This material is vaporized from the target (in a plasma plume) which deposits it as a thin film on a substrate (such as a silicon wafer facing the target). This process can occur in ultra high vacuum or in the presence of a background gas, such as oxygen which is commonly used when depositing oxides to fully oxygenate the deposited films.
In some embodiments, the YSZ layer is deposited at a temperature of about 700 °C to about 800 °C. In other embodiments, the temperature is about 700 °C to about 780 °C, about 700 °C to about 760 °C, about 700 °C to about 740 °C, or about 700 °C to about 720 °C.
In some embodiments, the YSZ layer is deposited at a pressure of about 10 7 Torr to about 104 Torr, or about 10 6 Torr to about 10 5 Torr.
In some embodiments, the CeC>2 layer is deposited via pulsed laser deposition (PLD).
In some embodiments, the CeC>2 layer is deposited at a temperature of about 700 °C to about 800 °C. In other embodiments, the temperature is about 700 °C to about 780 °C, about 700 °C to about 760 °C, about 700 °C to about 740 °C, or about 700 °C to about 720 °C.
In some embodiments, the CeC>2 layer is deposited at a pressure of about 10 7 Torr to about 104 Torr, or about 10 6 Torr to about 10 5 Torr.
In some embodiments, the DSO layer is deposited via pulsed laser deposition (PLD).
14
In some embodiments, the DSO layer is deposited at a temperature of about 700 °C to about 800 °C. In other embodiments, the temperature is about 700 °C to about 780 °C, about 700 °C to about 760 °C, about 700 °C to about 740 °C, or about 700 °C to about 720 °C.
In some embodiments, the DSO layer is deposited at a pressure of about 80 mTorr to about 150 mTorr. In other embodiments, the pressure is about 80 mTorr to about 140 mTorr, about 80 mTorr to about 130 mTorr, about 80 mTorr to about 120 mTorr, about 80 mTorr to about 110 mTorr, or about 80 mTorr to about 100 mTorr.
For example, Yttria-stabilized zirconia (YSZ) layer can be first deposited on silicon at high vacuum and 720 °C by pulsed laser deposition (PLD). This approach is very effective in removing any extra silicon dioxide. Subsequently, CeC>2 can be deposited on YSZ under the same vacuum condition and temperature to provide a beneficial chemical buffer layer between YSZ and oxide thin film (like DSO) and also to overcome the lattice mismatch between them. Finally, DSO can be deposited on the YSZ/Ce02 layer at 100 mTorr and 720 °C. The X-ray diffraction (XRD) spectra confirmed the epitaxial growth of DySc03, as shown in Figure 1.
The present invention also provides a dysprosium scandate film, comprising: a) a silicon wafer; b) a Yttria-stabilized zirconia (YSZ) layer on the silicon wafer; c) a Ce02 layer on the YSZ layer; and d) a dysprosium scandate (DSO) layer on the Ce02 layer; wherein the DSO layer has an X-ray diffraction peak with a full width of half maximum (FWHM) value of about 0.220° to about 0.300°.
As the silicon wafer is treated with alcohol as disclosed herein, single crystals with low defects can be grown or deposited on its etched surface.
15
In some embodiments, the DSO layer has an X-ray diffraction peak at about 22° to about 23°. In other embodiments, the X-ray diffraction peak at about 22° to about 22.9°, about 22° to about 22.8°, about 22° to about 22.7°, about 22° to about 22.6°, about 22° to about 22.5°, about 22° to about 22.4°, about 22° to about 22.3°, about 22° to about 22.2°, or about 22.1° to about 22.2°.
In some embodiments, the DSO layer has an X-ray diffraction peak with a full width of half maximum (FWHM) value of about 0.230° to about 0.300°, about 0.240° to about 0.300°, about 0.250° to about 0.300°, about 0.260° to about 0.300°, about 0.270° to about 0.300°, or about 0.280° to about 0.300°. In other embodiments, the FWHM is about 0.230° to about 0.290°, about 0.240° to about 0.290°, or about 0.240° to about 0.280°.
In some embodiments, the YSZ layer has a thickness of about 15 nm to about 40 nm. In other embodiments, the thickness is about 15 nm to about 38 nm, about 15 nm to about 36 nm, about 15 nm to about 34 nm, about 15 nm to about 32 nm, about 15 nm to about 30 nm, about 16 nm to about 30 nm, about 18 nm to about 30 nm, about 20 nm to about 30 nm, about 22 nm to about 30 nm, about 24 nm to about 30 nm, or about 26 nm to about 30 nm.
In some embodiments, the CeC>2 layer has a thickness of about 30 nm to about 60 nm. In other embodiments, the thickness is about 30 nm to about 58 nm, about 30 nm to about 56 nm, about 30 nm to about 54 nm, about 30 nm to about 52 nm, about 30 nm to about 50 nm, about 32 nm to about 50 nm, about 34 nm to about 50 nm, about 36 nm to about 50 nm, about 38 nm to about 50 nm, about 40 nm to about 50 nm, about 40 nm to about 48 nm, about 40 nm to about 46 nm, or about 40 nm to about 44 nm.
In some embodiments, the DSO layer has a thickness of about 15 nm to about 40 nm. In other embodiments, the thickness is about 15 nm to about 38 nm, about 15 nm to about 36 nm, about 15 nm to about 34 nm, about 15 nm to about 32 nm, about 15 nm to about 30 nm, about 16 nm to about 30 nm, about
16
18 nm to about 30 nm, about 20 nm to about 30 nm, about 20 nm to about 28 nm, about 20 nm to about 26 nm, about 20 nm to about 24 nm, or about 20 nm to about 22 nm.
In some embodiments, the YSZ layer is a YSZ epitaxial layer. Epitaxy refers to a type of crystal growth or material deposition in which new crystalline layers are formed with one or more well-defined orientations with respect to the crystalline substrate. The deposited crystalline film is called an epitaxial film or epitaxial layer. The relative orientation(s) of the epitaxial layer to the crystalline substrate is defined in terms of the orientation of the crystal lattice of each material. For epitaxial growth, the new layer must be crystalline and each crystallographic domain of the overlayer must have a well-defined orientation relative to the substrate crystal structure. Amorphous growth or multicrystalline growth with random crystal orientation does not meet this criterion.
In some embodiments, the crystal orientation of YSZ layer is [001].
In some embodiments, the CeC>2 layer is a CeC>2 epitaxial layer. In some embodiments, the crystal orientation of CeC>2 layer is [001].
In some embodiments, the DSO layer is a DSO epitaxial layer. In some embodiments, the crystal orientation of DSO layer is [001].
The X-ray diffraction rocking curve of DySc03 has a full width of half maximum (FWHM) value of 0.285°, as shown in Figure 2, which shows an excellent crystallinity. With this high-quality single-crystal thin films (Si/YSZ/Ce02/DSO), multiple oxide thin films can be deposited on it.
The atom-resolution scanning transmission electron microscopy (STEM) images of DSO buffer layers show a distinct contrast among different buffer layers of DSO/Ce02/YSZ. The epitaxy relationship is well maintained in the Ce02/YSZ buffered layer case, but there is a small off tilt between DSO and Ce02,
17
originated from the symmetry mismatch between DSO and CeC>2. The DSO crystal structure and atoms can be observed in the zoom image of the DSO layer, which confirms the high-quality crystallinity of the DSO.
The high-quality single-crystal DSO thin film grown on silicon was achieved. The FWHM value of the DSO is about 0.285° (fitting using Matlab), which is very good as a buffer layer. The high-resolution STEM images also confirmed the epitaxial growth mode and good crystallinity of DSO film. The DSO layer will provide a platform for depositing functional materials and further the device design. This platform allows for integration of innumerable multifunctional oxide materials into a silicon platform used in the semiconductor industry for designing various high-performance devices, such as an ultrahigh-speed optical modulator.
In some embodiments, the DSO layer is characterised by a X-ray diffraction peak with a FWHM value of about 0.2° to about 0.4°, about 0.2° to about 0.3.8°, about 0.2° to about 0.36°, about 0.2° to about 0.34°, about 0.2° to about 0.32°, about 0.2° to about 0.3°, about 0.22° to about 0.3°, about 0.24° to about 0.3°, about 0.26° to about 0.3°, or about 0.28° to about 0.3°.
The FWHM (full width half maximum) value of rocking curve obtained from an x-ray diffraction analysis of the DSO film on silicon is about 0.242°, indicating a high degree of crystal quality. This result can be obtained by fitting using the SPEC software which is a control software of the x-ray diffraction instrument.
Accordingly, in some embodiments, the method of fabricating a dysprosium scandate film on an etched surface of a silicon wafer removed from an etchant, comprises: a) contacting the etched surface of the silicon wafer with an alcohol for at least 1 h in order to allow alkoxy moieties to be chemisorbed on the etched surface of the silicon wafer; b) depositing a Yttria-stabilized zirconia (YSZ) layer on the etched surface;
18
c) depositing a CeC>2 layer on the YSZ layer; and d) depositing a dysprosium scandate (DSO) layer on the CeC>2 layer; wherein the DSO layer is characterised by a X-ray diffraction peak with a FWHM value of about 0.2° to about 0.4°.
In summary, the integration of DSO onto a silicon wafer provides a platform for depositing innumerable multifunctional oxide materials on silicon wafers for designing various high-performance devices because a DSO single crystal can be a good substrate for epitaxial films. Additionally, because of the low oxidation state of the etched surface of the silicon wafer, a high quality of the buffer layers can be obtained. It is thus much easier to deposit high-quality epitaxial films when the quality of the buffer layers is high. The method preventing and/or reducing oxidation of silicon wafer provides an epitaxial growth template for the growth of oxide thin films using a physical deposition technique, which is crucial for growing high-quality DSO films.
It will be appreciated that many further modifications and permutations of various aspects of the described embodiments are possible. Accordingly, the described aspects are intended to embrace all such alterations, modifications, and variations that fall within the spirit and scope of the appended claims.
Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.
Throughout this specification and the claims which follow, unless the context requires otherwise, the phrase "consisting essentially of", and variations such as "consists essentially of" will be understood to indicate that the recited element(s) is/are essential i.e. necessary elements of the invention. The phrase allows for the presence of other non-recited elements which do not materially
19
affect the characteristics of the invention but excludes additional unspecified elements which would affect the basic and novel characteristics of the method defined. The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.
20
Claims
1. A method of fabricating a dysprosium scandate film on an etched surface of a silicon wafer immersed in an etchant, comprising: a) contacting the etched surface of the silicon wafer with an alcohol for at least 1 h in order to allow alkoxy moieties to be chemisorbed on the etched surface of the silicon wafer; b) depositing a Yttria-stabilized zirconia (YSZ) layer on the etched surface; c) depositing a CeC>2 layer on the YSZ layer; and d) depositing a dysprosium scandate (DSO) layer on the CeC>2 layer.
2. The method according to claim 1, wherein the etched surface is contacted with the alcohol within less than about 10 s after removal of the silicon wafer from the etchant.
3. The method according to claim 1 or 2, wherein the alcohol is selected from methanol, ethanol, iso-propanol and/or n-propanol.
4. The method according to any one of claims 1 to 3, wherein the alcohol has a purity of more than about 90% and/or a water content of less than about 1%.
5. The method according to any one of claims 1 to 4, wherein the alcohol is purged with an inert gas and/or is de-gassed.
6. The method according to any one of claims 1 to 5, wherein the etched surface on the silicon wafer is contacted with the alcohol under oxygen free conditions.
7. The method according to any one of claims 1 to 6, wherein the etched surface on the silicon wafer is contacted with the alcohol for about 1 h to about 24 h and/or at a temperature of about 5 °C to about 50 °C.
21
8. The method according to any one of claims 1 to 7, further comprising a step of cleaning the etched surface of the silicon wafer in order for the etched surface to be free of the etchant.
9. The method according to any one of claims 1 to 8, wherein the etchant is selected from Piranha, hydrofluoric acid, ammonia water, hydrogen peroxide and/or hydrochloric acid.
10. The method according to any one of claims 1 to 9, wherein the YSZ layer is deposited via pulsed laser deposition (PLD).
11. The method according to any one of claims 1 to 10, wherein the YSZ layer is deposited at a temperature of about 700 °C to about 800 °C and/or at a pressure of about 10 6 Torr to about 10 5 Torr.
12. The method according to any one of claims 1 to 11, wherein the CeC>2 layer is deposited via pulsed laser deposition (PLD).
13. The method according to any one of claims 1 to 12, wherein the CeC>2 layer is deposited at a temperature of about 700 °C to about 800 °C and/or at a pressure of about 10 6 Torr to about 10 5 Torr.
14. The method according to any one of claims 1 to 13, wherein the DSO layer is deposited via pulsed laser deposition (PLD).
15. The method according to any one of claims 1 to 14, wherein the DSO layer is deposited at a temperature of about 700 °C to about 800 °C and/or at a pressure of about 80 mTorr to about 150 mTorr.
16. The method according to any one of claims 1 to 15, wherein the DSO layer is characterised by a X-ray diffraction peak with a full width of half maximum (FWHM) value of about 0.22° to about 0.3°.
22
17. A dysprosium scandate film, comprising: a) a silicon wafer; b) a Yttria-stabilized zirconia (YSZ) layer on the silicon wafer; c) a CeC>2 layer on the YSZ layer; and d) a dysprosium scandate (DSO) layer on the CeC>2 layer; wherein the DSO layer is characterised by a X-ray diffraction peak with a full width of half maximum (FWHM) value of about 0.220° to about 0.300°.
18. The dysprosium scandate film according to claim 17, wherein the DSO layer has an X-ray diffraction peak at about 22° to about 23°.
19. The dysprosium scandate film according to claim 17 or 18, wherein the YSZ layer has a thickness of about 15 nm to about 40 nm.
20. The dysprosium scandate film according to any one of claims 17 to 19, wherein the Ce02 layer has a thickness of about 30 nm to about 60 nm.
21. The dysprosium scandate film according to any one of claims 17 to 20, wherein the DSO layer has a thickness of about 15 nm to about 40 nm.
22. The dysprosium scandate film according to any one of claims 17 to 21, wherein the YSZ layer is a YSZ epitaxial layer.
23. The dysprosium scandate film according to any one of claims 17 to 22, wherein the Ce02 layer is a Ce02 epitaxial layer.
24. The dysprosium scandate film according to any one of claims 17 to 23, wherein the DSO layer is a DSO epitaxial layer.
23
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SG10202104861P | 2021-05-10 | ||
SG10202104861P | 2021-05-10 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2022240357A1 true WO2022240357A1 (en) | 2022-11-17 |
Family
ID=84029907
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/SG2022/050300 WO2022240357A1 (en) | 2021-05-10 | 2022-05-10 | Dysprosium scandate films, methods of fabrication and uses thereof |
Country Status (1)
Country | Link |
---|---|
WO (1) | WO2022240357A1 (en) |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5358925A (en) * | 1990-04-18 | 1994-10-25 | Board Of Trustees Of The Leland Stanford Junior University | Silicon substrate having YSZ epitaxial barrier layer and an epitaxial superconducting layer |
-
2022
- 2022-05-10 WO PCT/SG2022/050300 patent/WO2022240357A1/en active Application Filing
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5358925A (en) * | 1990-04-18 | 1994-10-25 | Board Of Trustees Of The Leland Stanford Junior University | Silicon substrate having YSZ epitaxial barrier layer and an epitaxial superconducting layer |
Non-Patent Citations (5)
Title |
---|
EPITAXIAL OXIDES ON SILICON BY PULSED LASER DEPOSITION, 3 November 2017 (2017-11-03), Retrieved from the Internet <URL:https://research.utwente.nl/en/publications/epitaxial-oxides-on-silicon-by-pulsed-laser-deposition> [retrieved on 20220829] * |
SCIGAJ, M ET AL.: "Ultra-flat BaTi03 epitaxial films on Si (001) with large out- of-plane polarization", APPLIED PHYSICS LETTERS, vol. 102, no. 11, 20 March 2013 (2013-03-20), pages 112905, XP012171556, [retrieved on 20220829], DOI: 10.1063/1.4798246 * |
WAGNER, M. ET AL.: "Preparation and Characterization of Rare Rarth Scandate Thin Films as an Alternative Gate Dielectric", MRS ONLINE PROCEEDINGS LIBRARY, vol. 917, no. 1, 1 December 2006 (2006-12-01), pages 510, XP027986846, [retrieved on 20220829], DOI: 10.1557/PROC-0917-E05-10 * |
YAMADA, T. ET AL.: "Epitaxial growth of SrTi03 films on Ce02/yttria-stabilized zirconia/Si(001) with Ti02 atomic layer by pulsed- laser deposition", APPLIED PHYSICS LETTERS, vol. 83, no. 23, 2 December 2003 (2003-12-02), pages 4815 - 4817, XP001193057, [retrieved on 20220829], DOI: 10.1063/1.1631741 * |
ZHAO CHAO, HEEG TASSILO, WAGNER MARTIN, SCHUBERT JURGEN, WITTERS THOMAS, BRIJS BERT, BENDER HUGO, RICHARD OLIVIER, AFANAS'EV VALER: "Rare-Earth Metal Scandate High-k Layers", ECS TRANSACTIONS, ELECTROCHEMICAL SOCIETY, US, vol. 1, no. 5, 7 July 2006 (2006-07-07), US , pages 161 - 175, XP093006928, ISSN: 1938-5862, DOI: 10.1149/1.2209266 * |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP4486753B2 (en) | Method for obtaining a monocrystalline germanium layer on a monocrystalline silicon substrate and the product obtained thereby | |
KR101156721B1 (en) | METHOD FOR GROWING SINGLE CRYSTAL GaN ON SILICON | |
CN100372063C (en) | Group III nitride semiconductor substrate and its manufacturing method | |
KR101281684B1 (en) | Fabrication method of nitride semiconductor substrate | |
Tatsuyama | Molecular beam epitaxy of SrTiO3 films on Si (100)-2× 1 with SrO buffer layer | |
US11380543B2 (en) | Method for fabricating a monocrystalline structure | |
CN112687526B (en) | Preparation method of nitride semiconductor material and annealing treatment method thereof | |
US6906351B2 (en) | Group III-nitride growth on Si substrate using oxynitride interlayer | |
US20030015704A1 (en) | Structure and process for fabricating semiconductor structures and devices utilizing the formation of a compliant substrate for materials used to form the same including intermediate surface cleaning | |
EP4104214A1 (en) | Method and system for diffusing magnesium in gallium nitride materials using sputtered magnesium sources | |
WO2022240357A1 (en) | Dysprosium scandate films, methods of fabrication and uses thereof | |
JP7162833B2 (en) | Semiconductor device manufacturing method | |
US20200232119A1 (en) | Method of forming single-crystal group-iii nitride | |
US7129184B2 (en) | Method of depositing an epitaxial layer of SiGe subsequent to a plasma etch | |
US6693033B2 (en) | Method of removing an amorphous oxide from a monocrystalline surface | |
Aoyama et al. | Surface cleaning for Si epitaxy using photoexcited fluorine gas | |
JPH09260289A (en) | Growth method of compound semiconductor single crystal | |
WO2018066289A1 (en) | Semiconductor element substrate, etching method, and etching solution | |
US7101435B2 (en) | Methods for epitaxial silicon growth | |
KR100329206B1 (en) | Method for Growth of Thin Film Using an Interfacing Layer | |
JP2608448B2 (en) | Processing method of GaAs substrate | |
JP2874262B2 (en) | Method for manufacturing semiconductor device | |
Sudhakar et al. | Liquid phase epitaxial growth of II–V semiconductor compound Zn3As2 | |
CN116555724A (en) | Method for preparing monoatomic layer nitride | |
JP2022529804A (en) | Semiconductor structure and method |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 22807953 Country of ref document: EP Kind code of ref document: A1 |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
122 | Ep: pct application non-entry in european phase |
Ref document number: 22807953 Country of ref document: EP Kind code of ref document: A1 |