Abstract: An etching method includes: applying a radiation to an etching aqueous solution; and etching a material to be etched by using the etching aqueous solution irradiated with the radiation.

Abstract: A semiconductor device includes: a nitride semiconductor multilayer; an insulating film disposed on the nitride semiconductor multilayer; and a gate electrode disposed on the insulating film, wherein the nitride semiconductor multilayer has a first oxidized region near an interface with a region of the insulating film below the gate electrode, the first oxidized region having an oxygen concentration higher than an oxygen concentration of a region near an interface with a region of the insulating film other than below the gate electrode.

Abstract: A semiconductor device includes a substrate, a first semiconductor layer formed over the substrate, the first semiconductor layer being composed of a nitride semiconductor, a second semiconductor layer formed over the first semiconductor layer, the second semiconductor layer being composed of a nitride semiconductor and a gate electrode, a source electrode, and a drain electrode that are formed over the second semiconductor layer, wherein the source electrode including a plurality of protrusions that penetrate into the second semiconductor layer, and the protrusions having a side surface inclined with respect to a surface of the first semiconductor layer.

Abstract: A semiconductor device includes: a first semiconductor layer formed, on a substrate, of a nitride semiconductor; a second semiconductor layer formed, on the first semiconductor layer, of a nitride semiconductor; a source electrode formed on the second semiconductor layer; a drain electrode formed on the second semiconductor layer; a metal oxide film formed, between the source electrode and the drain electrode, on the second semiconductor layer; and a gate electrode formed on the metal oxide film. The metal oxide film includes AlOx and InOx. AlOx/InOx in the metal oxide film is greater than or equal to 3.

Abstract: A semiconductor device includes: a first semiconductor layer formed, on a substrate, of a nitride semiconductor; a second semiconductor layer formed, on the first semiconductor layer, of a nitride semiconductor; a source electrode formed on the second semiconductor layer; a drain electrode formed on the second semiconductor layer; a metal oxide film formed, between the source electrode and the drain electrode, on the second semiconductor layer; and a gate electrode formed on the metal oxide film. The metal oxide film includes AlOx and InOx. AlOx/InOx in the metal oxide film is greater than or equal to 3.

Abstract: A semiconductor device includes a first semiconductor layer formed of a compound semiconductor, provided over a substrate; a second semiconductor layer formed of a compound semiconductor including In and Al, provided over the first semiconductor layer; source and drain electrodes provided on the second semiconductor layer; and a gate electrode provided between the source and drain electrodes, on the second semiconductor layer. The compound semiconductor in the second semiconductor layer has a first In composition ratio in a region on a side facing the substrate and a second In composition ratio in a region on an opposite side, the second In composition ratio being lower than the first In composition ratio, and the source and drain electrodes are provided in contact with the region having the first In composition ratio, and the gate electrode is provided on the region having the second In composition ratio.

Abstract: A compound semiconductor device includes: a carrier transit layer; a carrier supply layer over the carrier transit layer; a source electrode and a drain electrode above the carrier supply layer; a gate electrode above the carrier supply layer between the source electrode and the drain electrode; and a first insulating film and a second insulating film above the carrier supply layer between the gate electrode and the drain electrode. The gate electrode includes a portion above the second insulating film, the second insulating film covers a side surface of the first insulating film from the drain electrode side, and a second concentration of electron traps in the second insulating film is higher than a first concentration of electron traps in the first insulating film.

Abstract: A semiconductor device includes a compound semiconductor layer, a gate electrode, and first and second insulating layers. The first insulating layer covers the gate electrode on the compound semiconductor layer and has a cavity that surrounds the gate electrode. The second insulating layer is provided on the first insulating layer and has an opening at a position corresponding to the cavity. A part of the second insulating layer, which is provided on the first insulating layer that covers the gate electrode, corresponding to the cavity is removed via the opening, so that the generation of parasitic capacitance due to the second insulating layer is suppressed.

Abstract: A compound semiconductor device includes: a carrier transit layer; a carrier supply layer over the carrier transit layer; a source electrode and a drain electrode above the carrier supply layer; a gate electrode above the carrier supply layer between the source electrode and the drain electrode; and a first insulating film, a second insulating film, and a third insulating film above the carrier supply layer between the gate electrode and the drain electrode. The gate electrode includes a portion above the third insulating film, a first concentration of electron traps in the first insulating film is higher than a second concentration of electron traps in the second insulating film, and a third concentration of electron traps in the third insulating film is higher than the second concentration of the electron traps in the second insulating film.

Abstract: A semiconductor device includes: a semiconductor layer; a first insulating film which covers a surface of the semiconductor layer; a first adhering film which is formed on a surface of the first insulating film and contains a carbonyl group; and a second insulating film which covers a surface of the first adhering film and has a lower dielectric constant than the first insulating film.

Abstract: A semiconductor device includes a first semiconductor layer formed of a nitride semiconductor, on a substrate; a second semiconductor layer formed of a nitride semiconductor, on the first semiconductor layer; a source electrode and a drain electrode formed on the second semiconductor layer; a first insulating film formed on the second semiconductor layer; a second insulating film formed on the first insulating film; and a gate electrode formed on the second insulating film. The first insulating film includes a nitride film formed on a side of the second semiconductor layer, and an oxynitride film formed on the nitride film, and the second insulating film is formed of an oxide.

Abstract: A semiconductor device includes: a semiconductor layer; a first insulating film which covers a surface of the semiconductor layer; a first adhering film which is formed on a surface of the first insulating film and contains a carbonyl group; and a second insulating film which covers a surface of the first adhering film and has a lower dielectric constant than the first insulating film.

Abstract: A method of fabricating a semiconductor device may form a nitride semiconductor layer on a substrate, form a first insulator layer on the nitride semiconductor layer by steam oxidation of ALD, form a second insulator layer on the first insulator layer by oxygen plasma oxidation of ALD, form a gate electrode on the second insulator layer, and form a source and drain electrodes on the nitride semiconductor layer. The nitride semiconductor layer may include a first semiconductor layer on the substrate, and a second semiconductor layer on the first semiconductor layer.

Abstract: A compound semiconductor device includes a first protection film which covers a surface of a compound semiconductor layer, where the first protection film is an insulating film whose major constituent is Si and at least one element between N and O, and a hydrophobic layer containing Si—CxHy is formed at a surface thereof.

Abstract: A semiconductor device includes a semiconductor stacked structure in which a semiconductor layer including an electron supply layer and an electron transit layer is stacked, and a gate electrode contacting with the semiconductor layer included in the semiconductor stacked structure or an insulating layer. The portion of the gate electrode contacting with the semiconductor layer or the insulating layer is an oxide of a metal configuring the portion of the gate electrode contacting with the semiconductor layer or the insulating layer.

Abstract: A semiconductor device includes a compound semiconductor layer, a gate electrode, and first and second insulating layers. The first insulating layer covers the gate electrode on the compound semiconductor layer and has a cavity that surrounds the gate electrode. The second insulating layer is provided on the first insulating layer and has an opening at a position corresponding to the cavity. A part of the second insulating layer, which is provided on the first insulating layer that covers the gate electrode, corresponding to the cavity is removed via the opening, so that the generation of parasitic capacitance due to the second insulating layer is suppressed.

Abstract: A semiconductor device includes a first semiconductor layer made of a nitride semiconductor and formed on a substrate, a second semiconductor layer made of a material including InAlN and formed on the first semiconductor layer, an insulator layer formed by an oxidized surface part of the second semiconductor layer, a gate electrode formed on the insulator layer, and a source electrode and a drain electrode respectively formed on the first or second semiconductor layer.

Abstract: A method of producing a semiconductor device includes forming an insulating film on a substrate on which a semiconductor layer is formed; removing a part of the insulating film by etching to form an opening in the insulating film; supplying steam with a temperature greater than or equal to 200° C. and less than or equal to 600° C. to the opening formed in the insulating film; after supplying the steam, applying a solution including a silicon compound to a side surface of the insulating film defining the opening; and forming a hydrophobic film on the side surface of the insulating film defining the opening by polymerizing the silicon compound.

Abstract: A semiconductor device includes a semiconductor stacked structure in which a semiconductor layer including an electron supply layer and an electron transit layer is stacked, and a gate electrode contacting with the semiconductor layer included in the semiconductor stacked structure or an insulating layer. The portion of the gate electrode contacting with the semiconductor layer or the insulating layer is an oxide of a metal configuring the portion of the gate electrode contacting with the semiconductor layer or the insulating layer.

Abstract: A semiconductor device includes a first semiconductor layer formed of a compound semiconductor, provided over a substrate; a second semiconductor layer formed of a compound semiconductor including In and Al, provided over the first semiconductor layer; source and drain electrodes provided on the second semiconductor layer; and a gate electrode provided between the source and drain electrodes, on the second semiconductor layer. The compound semiconductor in the second semiconductor layer has a first In composition ratio in a region on a side facing the substrate and a second In composition ratio in a region on an opposite side, the second In composition ratio being lower than the first In composition ratio, and the source and drain electrodes are provided in contact with the region having the first In composition ratio, and the gate electrode is provided on the region having the second In composition ratio.