A resistor-transistor-logic circuit with GaN structures, including a 2DEG resistor having a drain connected with an operating voltage, and a logic FET having a gate connected to an input voltage, a source grounded and a drain connected with a source of the 2DEG resistor and connected collectively to an output voltage.

A parasitic capacitance and a leak current in a nitride semiconductor device are reduced. For example, a 100 nm-thick buffer layer made of AlN, a 2 μm-thick undoped GaN layer, and 20 nm-thick undoped AlGaN having an Al composition ratio of 20% are epitaxially grown in this order on, for example, a substrate made of silicon, and a source electrode and a drain electrode are formed so as to be in ohmic contact with the undoped AlGaN layer. Further, in the undoped GaN layer and the undoped AlGaN layer immediately below a gate wire, a high resistance region, the resistance of which is increased by, for example, ion implantation with Ar or the like, is formed, and a boundary between the high resistance region and an element region is positioned immediately below the gate wire.

A normally-off HEMT transistor includes a heterostructure including a channel layer and a barrier layer on the channel layer; a 2DEG layer in the heterostructure; an insulation layer in contact with a first region of the barrier layer; and a gate electrode through the whole thickness of the insulation layer, terminating in contact with a second region of the barrier layer. The barrier layer and the insulation layer have a mismatch of the lattice constant (“lattice mismatch”), which generates a mechanical stress solely in the first region of the barrier layer, giving rise to a first concentration of electrons in a first portion of the two-dimensional conduction channel which is under the first region of the barrier layer which is greater than a second concentration of electrons in a second portion of the two-dimensional conduction channel which is under the second region of the barrier layer.

A semiconductor structure and a method of forming the same are provided. In an embodiment, an exemplary semiconductor structure includes a gate structure. The gate structure includes a gate dielectric layer, an n-type work function layer embedded in the gate dielectric layer, a dielectric capping layer embedded in the n-type work function layer, and a p-type work function layer embedded in the dielectric capping layer. A top surface of the gate structure exposes the n-type work function layer, the dielectric capping layer, and the p-type work function layer. The semiconductor structure also includes a first metal cap on the n-type work function layer and a second metal cap on the p-type work function layer. The first metal cap is spaced apart from the second metal cap. without formed on the dielectric capping layer.

A nitride semiconductor device includes a substrate, a drift layer and a block layer sequentially provided above the substrate, a gate opening penetrating through a block layer and reaching a drift layer, an electron transit layer and an electron supply layer sequentially provided above the block layer and along the inner surface of the gate opening, a gate electrode provided to cover the gate opening, a source opening penetrating through an electron supply layer and an electron transit layer and reaching the block layer, a source electrode provided in the source opening, and a drain electrode on the rear surface side of the substrate. Seen in a plan view, at least part of an outline of an end of the gate opening in the longitudinal direction follows an arc or an elliptical arc.

A high electron mobility transistor includes: a first semiconductor layer over a substrate, and a second semiconductor layer over the first semiconductor layer, the second semiconductor layer having a band gap discontinuity with the first semiconductor layer, and at the first semiconductor layer and/or the second conductive layer includes indium. A top layer is over the second semiconductor layer, and a metal layer is over, and extends into, the top layer, the top layer separating the metal layer from the second semiconductor layer. A gate electrode is over the top layer, a third semiconductor layer being between the gate electrode and the top layer, where a sidewall of the third semiconductor layer and a sidewall of the metal layer are separated. A source and drain are on opposite sides of the gate electrode, the top layer extending continuously from below the source, below the gate electrode, and below the drain.

Embodiments are directed to high electron mobility transistor (HEMT) devices and methods. One such HEMT device includes a substrate having a first surface, and first and second heterostructures on the substrate and facing each other. Each of the first and second heterostructures includes a first semiconductor layer on the first surface of the substrate, a second semiconductor layer on the first surface of the substrate, and a two-dimensional electrode gas (2DEG) layer between the first and second semiconductor layers. A doped semiconductor layer is disposed between the first and second heterostructures, and a source contact is disposed on the first heterostructure and the second heterostructure.

A method for fabricating high electron mobility transistor (HEMT) includes the steps of: forming a buffer layer on a substrate; forming a patterned mask on the buffer layer; using the patterned mask to remove the buffer layer for forming ridges and a damaged layer on the ridges; removing the damaged layer; forming a barrier layer on the ridges; and forming a p-type semiconductor layer on the barrier layer.

A semiconductor device includes a first nitride-based semiconductor layer, a second nitride-based semiconductor layer, a group of negatively-charged ions, and a field plate. The gate electrode and the drain electrode disposed above the second nitride-based semiconductor layer to define a drift region therebetween. The group of negatively-charged ions are implanted into the drift region and spaced apart from an area directly beneath the gate and drain electrodes to form at least one high resistivity zone in the second nitride-based semiconductor layer. The field plate is disposed over the gate electrode and extends in a region between the gate electrode and the high resistivity zone.

There is provided a semiconductor layer structure (100) comprising: a Si substrate (102) having a top surface (104); a first semiconductor layer (110) arranged on said substrate, the first semiconductor layer comprising a plurality of vertical nanowire structures (112) arranged perpendicularly to said top surface of said substrate, the first semiconductor layer comprising AlN; a second semiconductor layer (120) arranged on said first semiconductor layer laterally and vertically enclosing said nanowire structures, the second semiconductor layer comprising Al.sub.xGa.sub.1-xN, wherein 0≤x≤0.95; a third semiconductor layer (130) arranged on said second semiconductor layer, the third semiconductor layer comprising Al.sub.yGa.sub.1-yN, wherein 0≤y≤0.95; and a fourth semiconductor layer (140) arranged on said third semiconductor layer, the fourth semiconductor layer comprising GaN. There is also provided a high-electron-mobility transistor device and methods of producing such structures and devices.