Methods are provided herein for forming transition metal oxide thin films, preferably Group IVB metal oxide thin films, by atomic layer deposition. The metal oxide thin films can be deposited at high temperatures using metalorganic reactants. Metalorganic reactants comprising two ligands, at least one of which is a cycloheptatriene or cycloheptatrienyl (CHT) ligand are used in some embodiments. The metal oxide thin films can be used, for example, as dielectric oxides in transistors, flash devices, capacitors, integrated circuits, and other semiconductor applications.

The invention provides a process for exfoliating a 3-dimensional layered material to produce a 2-dimensional material, said process comprising the steps of mixing the layered material in a solvent to provide a mixture; applying energy, for example ultrasound, to said mixture, and removing the energy applied to the mixture, such that sedimentation of the 2-dimensional material out of solution as a weakly re-aggregated, exfoliated 2-dimensional material is produced. The invention provides a fast, simple and high yielding process for separating 3-dimensional layered materials into individual 2-dimensional layers or flakes, which do not strongly re-aggregate, without utilising hazardous solvents.

The invention provides a process for exfoliating a 3-dimensional layered material to produce a 2-dimensional material, said process comprising the steps of mixing the layered material in a solvent to provide a mixture; applying energy, for example ultrasound, to said mixture, and removing the energy applied to the mixture, such that sedimentation of the 2-dimensional material out of solution as a weakly re-aggregated, exfoliated 2-dimensional material is produced. The invention provides a fast, simple and high yielding process for separating 3-dimensional layered materials into individual 2-dimensional layers or flakes, which do not strongly re-aggregate, without utilising hazardous solvents.

A semiconductor device according to an embodiment includes a first conductive layer, a second conductive layer, and a dielectric film provided between the first and the second conductive layers. The dielectric film including a fluorite-type crystal and a positive ion site includes Hf and/or Zr, and a negative ion site includes O. In the dielectric film, parameters a, b, c, p, x, y, z, u, v and w satisfy a predetermined relation. The axis length of the a-axis, b-axis and c-axis of the original unit cell is a, b, and c, respectively. An axis in a direction with no reversal symmetry is c-axis, a stacking direction of atomic planes of two kinds formed by negative ions disposed at different positions is a-axis, the remainder is b-axis. The parameters x, y, z, u, v and w are values represented using the parameter p.

A semiconductor device according to an embodiment includes a first conductive layer, a second conductive layer, and a dielectric film provided between the first and the second conductive layers. The dielectric film including a fluorite-type crystal and a positive ion site includes Hf and/or Zr, and a negative ion site includes O. In the dielectric film, parameters a, b, c, p, x, y, z, u, v and w satisfy a predetermined relation. The axis length of the a-axis, b-axis and c-axis of the original unit cell is a, b, and c, respectively. An axis in a direction with no reversal symmetry is c-axis, a stacking direction of atomic planes of two kinds formed by negative ions disposed at different positions is a-axis, the remainder is b-axis. The parameters x, y, z, u, v and w are values represented using the parameter p.

Methods are provided herein for forming transition metal oxide thin films, preferably Group IVB metal oxide thin films, by atomic layer deposition. The metal oxide thin films can be deposited at high temperatures using metalorganic reactants. Metalorganic reactants comprising two ligands, at least one of which is a cycloheptatriene or cycloheptatrienyl (CHT) ligand are used in some embodiments. The metal oxide thin films can be used, for example, as dielectric oxides in transistors, flash devices, capacitors, integrated circuits, and other semiconductor applications.

Methods are provided herein for forming transition metal oxide thin films, preferably Group IVB metal oxide thin films, by atomic layer deposition. The metal oxide thin films can be deposited at high temperatures using metalorganic reactants. Metalorganic reactants comprising two ligands, at least one of which is a cycloheptatriene or cycloheptatrienyl (CHT) ligand are used in some embodiments. The metal oxide thin films can be used, for example, as dielectric oxides in transistors, flash devices, capacitors, integrated circuits, and other semiconductor applications.

A method for recovering hafnium and impurity metals from a hafnium-containing waste residue, comprises dissolving the waste residue in sulfuric acid and ammonium sulfate to obtain an acidic solution, adjusting acidity of the acidic solution, and adding a complexing agent to obtain a material solution; conducting extraction to obtain a hafnium-loaded organic phase and an impurity metal ions-containing aqueous phase; subjecting the hafnium-loaded organic phase to purification, stripping, precipitation, and filtration, and washing and burning to obtain hafnium oxide; precipitating the impurity metal ions-containing aqueous phase, washing a resulting precipitate to remove the complexing agent; dissolving a resulting precipitates of the impurity metal ions in sulfuric acid, and adjusting acidity of a resulting solution to obtain a solution of the impurity metal ions; extracting the solution of the impurity metal ions to obtain an impurity metal ions-loaded organic phase, purifying and stripping to obtain oxides of the impurity metals.

A method for recovering hafnium and impurity metals from a hafnium-containing waste residue, comprises dissolving the waste residue in sulfuric acid and ammonium sulfate to obtain an acidic solution, adjusting acidity of the acidic solution, and adding a complexing agent to obtain a material solution; conducting extraction to obtain a hafnium-loaded organic phase and an impurity metal ions-containing aqueous phase; subjecting the hafnium-loaded organic phase to purification, stripping, precipitation, and filtration, and washing and burning to obtain hafnium oxide; precipitating the impurity metal ions-containing aqueous phase, washing a resulting precipitate to remove the complexing agent; dissolving a resulting precipitates of the impurity metal ions in sulfuric acid, and adjusting acidity of a resulting solution to obtain a solution of the impurity metal ions; extracting the solution of the impurity metal ions to obtain an impurity metal ions-loaded organic phase, purifying and stripping to obtain oxides of the impurity metals.

A hafnium compound-containing sol-gel liquid contains an alcohol as a solvent and a hafnium compound as a hafnia source, in which the hafnium compound-containing sol-gel liquid contains one or two or more elements M selected from the group consisting of Zr, Ti, and Nb, a mass ratio W.sub.M/W.sub.Hf of a content W.sub.M of the elements M to a content W.sub.Hf of Hf as a metal component is within a range of 0.2% or more and 5.0% or less. A hafnia-containing film containing hafnia (HfO.sub.2) and one or two or more elements M selected from the group consisting of Zr, Ti, and Nb, and in which a mass ratio W.sub.M/W.sub.HfO2 of a content W.sub.M of the elements M to a content W.sub.HfO2 of the HfO.sub.2 is within a range of 0.05% or more and 5.0% or less.