A semiconductor device (1) includes an insulated-gate field-effect transistor (2) that includes: a channel layer (21); a pair of main electrodes (24(s), 24(D)) spaced from each other and provided on the channel layer; a barrier layer (22) provided on the channel layer between the pair of main electrodes and including a recessed region (22A) that goes through the barrier layer in a thickness direction; a gate insulating film (25A, 25B) provided on the channel layer in the recessed region and having two or more kinds of thicknesses; and a gate electrode (26) provided on the channel layer through the gate insulating film.

A semiconductor device includes third active regions that connect two finger-end portions of field effect transistors (FETs) spaced apart from each other, and includes, above the third active regions, portions of a third nitride semiconductor layer that includes P-type impurities.

A semiconductor device including: a first silicon level including a first single crystal silicon layer and a plurality of first transistors; a first metal layer disposed over the first silicon level; a second metal layer disposed over the first metal layer; a third metal layer disposed over the second metal layer; a second level including a plurality of second transistors, disposed over the third metal layer; a third level including a plurality of third transistors, disposed over the second level; a via disposed through the second and third levels; a fourth metal layer disposed over the third level; a fifth metal layer disposed over the fourth metal layer; and a fourth level including a second single crystal silicon layer and is disposed over the fifth metal layer, where each of the plurality of second transistors includes a metal gate, and the via has a diameter of less than 650 nm.

A tunable breakdown voltage RF MESFET and/or MOSFET and methods of manufacture are disclosed. The method includes forming a first line and a second line on an underlying gate dielectric material. The second line has a width tuned to a breakdown voltage. The method further includes forming sidewall spacers on sidewalls of the first and second line such that the space between first and second line is pinched-off by the dielectric spacers. The method further includes forming source and drain regions adjacent outer edges of the first line and the second line, and removing at least the second line to form an opening between the sidewall spacers of the second line and to expose the underlying gate dielectric material. The method further includes depositing a layer of material on the underlying gate dielectric material within the opening, and forming contacts to a gate structure and the source and drain regions.

A tunable breakdown voltage RF MESFET and/or MOSFET and methods of manufacture are disclosed. The method includes forming a first line and a second line on an underlying gate dielectric material. The second line has a width tuned to a breakdown voltage. The method further includes forming sidewall spacers on sidewalls of the first and second line such that the space between first and second line is pinched-off by the dielectric spacers. The method further includes forming source and drain regions adjacent outer edges of the first line and the second line, and removing at least the second line to form an opening between the sidewall spacers of the second line and to expose the underlying gate dielectric material. The method further includes depositing a layer of material on the underlying gate dielectric material within the opening, and forming contacts to a gate structure and the source and drain regions.

A semiconductor device may include a first inverter, a second inverter, a first access transistor, and a second access transistor. A drain electrode of the first access transistor or a source electrode of the first access transistor may be electrically connected to both an output terminal of the first inverter and an input terminal the second inverter. The drain electrode of the first access transistor may be asymmetrical to the source electrode of the first access transistor with reference to a gate electrode of the first access transistor. A drain electrode of the second access transistor or a source electrode of the second access transistor may be electrically connected to both an output terminal of the second inverter and an input terminal the first inverter.

A tunable breakdown voltage RF MESFET and/or MOSFET and methods of manufacture are disclosed. The method includes forming a first line and a second line on an underlying gate dielectric material. The second line has a width tuned to a breakdown voltage. The method further includes forming sidewall spacers on sidewalls of the first and second line such that the space between first and second line is pinched-off by the dielectric spacers. The method further includes forming source and drain regions adjacent outer edges of the first line and the second line, and removing at least the second line to form an opening between the sidewall spacers of the second line and to expose the underlying gate dielectric material. The method further includes depositing a layer of material on the underlying gate dielectric material within the opening, and forming contacts to a gate structure and the source and drain regions.

A nitride semiconductor device includes a low resistance Si substrate that has a first principal surface and a second principal surface opposite thereto, a high resistance Si layer that is formed on the first principal surface and is higher in resistivity than the low resistance Si substrate, and a nitride epitaxial layer that is disposed on the high resistance Si layer.

A protection circuit includes a first insulated gate field-effect transistor in which: a first main electrode is coupled between an external terminal and an internal circuit; a second main electrode and a gate electrode are coupled to a reference power supply; and an electric charge accumulation section configured to accumulate hot carriers is provided in a gate insulating film.

A semiconductor device may include a first inverter, a second inverter, a first access transistor, and a second access transistor. A drain electrode of the first access transistor or a source electrode of the first access transistor may be electrically connected to both an output terminal of the first inverter and an input terminal the second inverter. The drain electrode of the first access transistor may be asymmetrical to the source electrode of the first access transistor with reference to a gate electrode of the first access transistor. A drain electrode of the second access transistor or a source electrode of the second access transistor may be electrically connected to both an output terminal of the second inverter and an input terminal the first inverter.