A method for growing a semiconductor material over a Si-based substrate includes providing the Si-based substrate; growing a monocrystalline refractory-metal ceramic film directly over the Si-based substrate; and depositing a semiconductor film directly over the monocrystalline refractory-metal ceramic film. The monocrystalline refractory-metal ceramic film has a thickness less than 300 nm.

To improve field-effect mobility and reliability of a transistor including an oxide semiconductor film. Provided is a semiconductor device including an oxide semiconductor film. The semiconductor device includes a first insulating film, the oxide semiconductor film over the first insulating film, a second insulating film and a third insulating film over the oxide semiconductor film, and a gate electrode over the second insulating film. The oxide semiconductor film includes a first oxide semiconductor film, a second oxide semiconductor film over the first oxide semiconductor film, and a third oxide semiconductor film over the second oxide semiconductor film. The first to third oxide semiconductor films contain the same element. The second oxide semiconductor film includes a region where the crystallinity is lower than the crystallinity of one or both of the first oxide semiconductor film and the third oxide semiconductor film.

In an aspect, a mixed metal oxide comprises or consists essentially of: a mixture comprises or consisting essentially of 0.30 to 0.69 parts by mole Mg, 0.20 to 0.69 parts by mole Zn, 0.01 to 0.30 parts by mole of a third element selected from Al and Ga, and, either, when the third element is Al, 0.00 to 0.31 parts by mole of other elements selected from metals and metalloids, or, when the third element is Ga, 0.00 to 0.15 parts by mole of other elements selected from metals and metalloids, wherein the sum of all parts by mole of Mg, Zn, the third element, and the other elements amounts to 1.00, wherein the amount in parts by mole of the other elements is lower than the amount in parts by mole of Mg and is lower than the amount in parts by mole of Zn; oxygen; and less than 0.01 parts by mole of non-metallic and non-metalloid impurities.

This invention in one aspect relates to a method of synthesizing a self-assembled mixed-dimensional heterostructure including 2D metallic borophene and 1D semiconducting armchair-oriented graphene nanoribbons (aGNRs). The method includes depositing boron on a substrate to grow borophene thereon at a substrate temperature in an ultrahigh vacuum (UHV) chamber; sequentially depositing 4,4″-dibromo-p-terphenyl on the borophene grown substrate at room temperature in the UHV chamber to form a composite structure; and controlling multi-step on-surface coupling reactions of the composite structure to self-assemble a borophene/graphene nanoribbon mixed-dimensional heterostructure. The borophene/aGNR lateral heterointerfaces are structurally and electronically abrupt, thus demonstrating atomically well-defined metal-semiconductor heterojunctions.

The invention relates to a method for producing a semiconductor structure, characterised in that the method comprises a step (201) of depositing a crystalline passivation layer continuously covering the entire surface of a layer based on group III nitrides, said crystalline passivation layer, which is deposited from a precursor containing silicon atoms and a flow of nitrogen atoms, consisting of silicon atoms bound to the surface of the layer based on group III nitrides and arranged in a periodical arrangement such that a diffraction image of said crystalline passivation layer obtained by grazing-incidence diffraction of electrons in the direction [1-100] comprises: two fractional order diffraction lines (0, −⅓) and (0, −⅔) between the central line (0, 0) and the integer order line (0, −1), and two fractional order diffraction lines (0, ⅓) and (0, ⅔) between the central line (0, 0) and the integer order line (0, 1).

After a sputtering gas is supplied to a deposition chamber, plasma including an ion of the sputtering gas is generated in the vicinity of a target. The ion of the sputtering gas is accelerated and collides with the target, so that flat-plate particles and atoms of the target are separated from the target. The flat-plate particles are deposited with a gap therebetween so that the flat plane faces a substrate. The atom and the aggregate of the atoms separated from the target enter the gap between the deposited flat-plate particles and grow in the plane direction of the substrate to fill the gap. A film is formed over the substrate. After the deposition, heat treatment is performed at high temperature in an oxygen atmosphere, which forms an oxide with a few oxygen vacancies and high crystallinity.

A sputtering method includes one or more sputtering processes. Each sputtering process includes in a first pre-sputtering phase, sputtering a target material on a baffle plate configured to shield a substrate; in a second pre-sputtering phase, sputtering a target material compound on the baffle plate; and in a main sputtering phase, sputtering the target material compound on the substrate. The first pre-sputtering phase is used to adjust a sputtering voltage for the main sputtering phase.

A transistor includes a multilayer film in which an oxide semiconductor film and an oxide film are stacked, a gate electrode, and a gate insulating film. The multilayer film overlaps with the gate electrode with the gate insulating film interposed therebetween. The multilayer film has a shape having a first angle between a bottom surface of the oxide semiconductor film and a side surface of the oxide semiconductor film and a second angle between a bottom surface of the oxide film and a side surface of the oxide film. The first angle is acute and smaller than the second angle. Further, a semiconductor device including such a transistor is manufactured.

An embodiment is a semiconductor device which includes a first oxide semiconductor layer over a substrate having an insulating surface and including a crystalline region formed by growth from a surface of the first oxide semiconductor layer toward an inside; a second oxide semiconductor layer over the first oxide semiconductor layer; a source electrode layer and a drain electrode layer which are in contact with the second oxide semiconductor layer; a gate insulating layer covering the second oxide semiconductor layer, the source electrode layer, and the drain electrode layer; and a gate electrode layer over the gate insulating layer and in a region overlapping with the second oxide semiconductor layer. The second oxide semiconductor layer is a layer including a crystal formed by growth from the crystalline region.

A field-effect transistor and method for fabricating such a field-effect transistor that utilizes an air-sensitive two-dimensional material (e.g., silicene). A film of air-sensitive two-dimensional material is deposited on a crystalized metallic (e.g., Ag) thin film on a substrate (e.g., mica substrate). A capping layer of insulating material (e.g., aluminum oxide) is deposited on the air-sensitive two-dimensional material. The substrate is detached from the metallic thin film/air-sensitive two-dimensional material/insulating material stack structure. The metallic thin film/air-sensitive two-dimensional material/insulating material stack structure is then flipped. The flipped metallic thin film/air-sensitive two-dimensional material/insulating material stack structure is attached to a device substrate followed by having the metallic thin film etched to form contact electrodes. In this manner, the pristine properties of air-sensitive two-dimensional materials are preserved from degradation when exposed to air. Furthermore, this new technique allows safe transfer and device fabrication of air-sensitive two-dimensional materials with a low material and process cost.