Gallium nitride (GaN) integrated circuit technology is described. In an example, an integrated circuit structure includes a substrate including silicon, the substrate having a top surface. A first trench is in the substrate, the first trench having a first width. A second trench is in the substrate, the second trench having a second width less than the first width. A first island is in the first trench, the first island including gallium and nitrogen and having first corner facets below the top surface of the substrate. A second island is in the second trench, the second island including gallium and nitrogen and having second corner facets below the top surface of the substrate.

A planar transistor device is disclosed including a gate structure positioned above a semiconductor substrate, the semiconductor substrate comprising a substantially planar upper surface, a channel region, a source region, a drain region, and at least one layer of a two-dimensional (2D) material that is positioned in at least one of the source region, the drain region or the channel region, wherein the layer of 2D material has a substantially planar upper surface, a substantially planar bottom surface and a substantially uniform vertical thickness across an entire length of the layer of 2D material in the gate length direction and across an entire width of the layer of 2D material in the gate width direction, wherein the substantially planar upper surface and the substantially planar bottom surface of the layer of 2D material are positioned approximately parallel to a substantially planar surface of the semiconductor substrate.

In a method of forming a two-dimensional material layer, a nucleation pattern is formed over a substrate, and a transition metal dichalcogenide (TMD) layer is formed such that the TMD layer laterally grows from the nucleation pattern. In one or more of the foregoing and following embodiments, the TMD layer is single crystalline.

A method of forming Si or Ge-based and III-V based vertically integrated nanowires on a single substrate and the resulting device are provided. Embodiments include forming first trenches in a Si, Ge, III-V, or Si.sub.xGe.sub.1-x substrate; forming a conformal SiN, SiO.sub.xC.sub.yN.sub.z layer over side and bottom surfaces of the first trenches; filling the first trenches with SiO.sub.x; forming a first mask over portions of the Si, Ge, III-V, or Si.sub.xGe.sub.1-x substrate; removing exposed portions of the Si, Ge, III-V, or Si.sub.xGe.sub.1-x substrate, forming second trenches; forming III-V, III-V.sub.xM.sub.y, or Si nanowires in the second trenches; removing the first mask and forming a second mask over the III-V, III-V.sub.xM.sub.y, or Si nanowires and intervening first trenches; removing the SiO.sub.x layer, forming third trenches; and removing the second mask.

Disclosed are semiconductor devices including a double gate metal oxide semiconductor (MOS) transistor and methods for fabricating the same. The double gate MOS transistor includes a first back gate, a second back gate, and a first dielectric layer disposed on the first back gate and on the second back gate. An MX2 material layer is disposed on the first dielectric layer, a second dielectric layer disposed on the MX2 material layer, and a work function metal (WFM) is disposed on the second dielectric layer. A front gate is disposed on the WFM, which fills a space between the first back gate and the second back.

A semiconductor device includes a substrate, a 2-D material layer, source/drain contacts, and a gate electrode. The 2-D material layer is over the substrate, the 2-D material layer includes source/drain regions and a channel region between the source/drain regions, in which the 2-D material layer is made of a transition metal dichalcogenide (TMD). The source/drain contacts are in contact with source/drain regions of the 2-D material layer, in which a binding energy of transition metal atoms at the channel region of the 2-D material layer is different from a binding energy of the transition metal atoms at the source/drain regions of the 2-D material layer. The gate electrode is over the substrate.

To further reduce contact resistance when a current or a voltage is taken out from a metal layer. A conductive structure including: an insulating layer; a metal layer provided on one surface of the insulating layer to protrude in a thickness direction of the insulating layer; and a two-dimensional material layer provided along outer shapes of the metal layer and the insulating layer from a side surface of the metal layer to the one surface of the insulating layer.

A two-dimensional semiconductor transistor includes a gate electrode, a gate insulating layer disposed on the gate electrode, an organic dopant layer disposed on the gate insulating layer and comprising an organic material including electrons, a two-dimensional semiconductor layer disposed on the organic dopant layer, a source electrode disposed on the two-dimensional semiconductor layer, and a drain electrode disposed on the two-dimensional semiconductor layer and spaced apart from the source electrode. A hysteresis of the two-dimensional semiconductor transistor is reduced due to the two-dimensional semiconductor transistor including the organic dopant layer.

Heterostructures include a layer of a two-dimensional material placed on a multiferroic layer. An ordered array of differing polarization domains in the multiferroic layer produces corresponding domains having differing properties in the two-dimensional material. When the multiferroic layer is ferroelectric, the ferroelectric polarization domains in the layer produce local electric fields that penetrate the two-dimensional material. The local electric fields modulate the charge carriers and carrier density on a nanometer length scale, resulting in the formation of lateral p-n or p-i-n junctions, and variations thereof appropriate for device functions.

Disclosed are semiconductor devices including a double gate metal oxide semiconductor (MOS) transistor and methods for fabricating the same. The double gate MOS transistor includes a first back gate, a second back gate, and a first dielectric layer disposed on the first back gate and on the second back gate. An MX2 material layer is disposed on the first dielectric layer, a second dielectric layer disposed on the MX2 material layer, and a work function metal (WFM) is disposed on the second dielectric layer. A front gate is disposed on the WFM, which fills a space between the first back gate and the second back.