Low-temperature fabrication of metal oxide thin films and nanomaterial-derived metal composite thin films

A method of fabricating a transistor device comprising a thin film semiconductor component comprising indium gallium zinc oxide (In—Ga—Zn—O), the method comprising:

• (a) depositing a thin film from a precursor composition comprising an indium salt, a gallium salt, and a zinc salt in a solvent or solvent mixture, wherein the indium salt, the gallium salt, and the zinc salt independently comprise either an oxidizing anion or a fuel anion, provided that (a) if none of the indium salt, the gallium salt and the zinc salt comprises a fuel anion, then the precursor composition further comprises either a fuel or an ammonium salt comprising a fuel anion, and (b) if none of the indium salt, the gallium salt and the zinc salt comprises an oxidizing anion, then the precursor composition further comprises either an acid comprising an oxidizing anion or an inorganic salt comprising an oxidizing anion, wherein:
• the fuel is selected from acetylacetone, CF3COCH2COCF3, CH3COCHFCOCH3, CH3COCH2C(═NH)CF3, CH3C(═NH)CHFC(═NH)CH3, CH3COCH2C(═NCH3)CF3, CH3C(═NCH3)CHFC(═NCH3)CH3, CH3C(═NH)CHFC(═NCH3)CH3, Ph2POCH2COCH3, urea, N-methylurea, citric acid, ascorbic acid, stearic acid, nitromethane, hydrazine, carbohydrazide, oxalyl dihydrazide, malonic acid dihydrazide, tetra formal tris azine, hexamethylenetetramine, and malonic anhydride,
• the fuel anion is selected from acetylacetonate, a citrate, an oxalate, an ascorbate, and a stearate,
• the oxidizing anion is selected from a nitrate, a perchlorate, a chlorate, a hypochlorite, an azide, a peroxide, a superoxide, a high-valent oxide, an N-oxide, a persulfate, a dinitramide, a nitrocyanamide, a nitroarylcarboxylate, a tetrazolate, and hydrates thereof, and
• the oxidizing anions and the fuel and fuel anions in the precursor composition are present in amounts to allow metal oxide formation and complete combustion of the fuel and fuel anions;
• (b) annealing the thin film at a temperature of less than or about 250° C. to initiate a combustion reaction between the oxidizing anions and the fuel and fuel anions, thereby forming a thin film semiconductor component comprising indium gallium zinc oxide (In—Ga—Zn—O) and converting the fuel and fuel anions into CO2, H2O, and optionally, N2;
• and
• (c) repeating steps (a) and (b) one or more times by depositing an overlying thin film on any previously deposited and annealed thin film, wherein each thin film formed by a single cycle of steps (a) and (b) has a thickness of less than or about 50 nm,
• to provide a transistor device comprising a thin film semiconductor component comprising indium gallium zinc oxide (In—Ga—Zn—O), wherein the transistor device exhibits a charge mobility of about 3 cm2/Vs or higher.

A method of fabricating a transistor device comprising a thin film semiconductor component comprising indium gallium zinc oxide (In—Ga—Zn—O), the method comprising:

• (a) depositing a thin film from a precursor composition comprising an indium salt, a gallium salt, and a zinc salt in a solvent or solvent mixture, wherein the indium salt, the gallium salt, and the zinc salt independently comprise either an oxidizing anion or a fuel anion, provided that (a) if none of the indium salt, the gallium salt and the zinc salt comprises a fuel anion, then the precursor composition further comprises either a fuel or an ammonium salt comprising a fuel anion, and (b) if none of the indium salt, the gallium salt and the zinc salt comprises an oxidizing anion, then the precursor composition further comprises either an acid comprising an oxidizing anion or an inorganic salt comprising an oxidizing anion, wherein:
• the fuel is selected from acetylacetone, CF3COCH2COCF3, CH3COCHFCOCH3, CH3COCH2C(═NH)CF3, CH3C(═NH)CHFC(═NH)CH3, CH3COCH2C(═NCH3)CF3, CH3C(═NCH3)CHFC(═NCH3)CH3, CH3C(═NH)CHFC(═NCH3)CH3, Ph2POCH2COCH3, urea, N-methylurea, citric acid, ascorbic acid, stearic acid, nitromethane, hydrazine, carbohydrazide, oxalyl dihydrazide, malonic acid dihydrazide, tetra formal tris azine, hexamethylenetetramine, and malonic anhydride,
• the fuel anion is selected from acetylacetonate, a citrate, an oxalate, an ascorbate, and a stearate,
• the oxidizing anion is selected from a nitrate, a perchlorate, a chlorate, a hypochlorite, an azide, a peroxide, a superoxide, a high-valent oxide, an N-oxide, a persulfate, a dinitramide, a nitrocyanamide, a nitroarylcarboxylate, a tetrazolate, and hydrates thereof, and
• the oxidizing anions and the fuel and fuel anions in the precursor composition are present in amounts to allow metal oxide formation and complete combustion of the fuel and fuel anions;
• (b) annealing the thin film at a temperature of less than or about 350° C., wherein the annealing step consists of heat treatment without irradiation, to initiate a combustion reaction between the oxidizing anions and the fuel and fuel anions, thereby forming a thin film semiconductor component comprising indium gallium zinc oxide (In—Ga—Zn—O) and converting the fuel and fuel anions into CO2, H2O, and optionally, N2;
• and
• (c) repeating steps (a) and (b) one or more times by depositing an overlying thin film on any previously deposited and annealed thin film, wherein each thin film formed by a single cycle of steps (a) and (b) has a thickness of less than or about 50 nm,
• to provide a transistor device comprising a thin film semiconductor component comprising indium gallium zinc oxide (In—Ga—Zn—O), wherein the transistor device exhibits a charge mobility of about 3 cm2/Vs or higher.