A semiconductor device comprises an active pattern on a substrate, a pair of first source/drain patterns on the active pattern, a pair of second source/drain patterns on top surfaces of the first source/drain patterns, a gate electrode extending across the active pattern and having sidewalls that face the first and second source/drain patterns, a first channel structure extending across the gate electrode and connecting the first source/drain patterns, and a second channel structure extending across the gate electrode and connecting the second source/drain patterns. The gate electrode includes a first lower part between a bottom surface of the first channel structure and a top surface of the active pattern, and a first upper part between a top surface of the first channel structure and a bottom surface of the second channel structure. The first lower part has a thickness greater than that of the first upper part.

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 semiconductor device may include first channels on a first region of a substrate and spaced apart from each other in a vertical direction substantially perpendicular to an upper surface of the substrate, second channels on a second region of the substrate and spaced apart from each other in the vertical direction, a first gate structure on the first region of the substrate and covering at least a portion of a surface of each of the first channels, and a second gate structure on the second region of the substrate and covering at least a portion of a surface of each of the second channels. The second channels may be disposed at heights substantially the same as those of corresponding ones of the first channels, and a height of a lowermost one of the second channels may be greater than a height of a lowermost one of the first channels.

A semiconductor body having a base carrier portion and a type III-nitride semiconductor portion is provided. The type III-nitride semiconductor portion includes a heterojunction and two-dimensional charge carrier gas. One or more ohmic contacts are formed in the type III-nitride semiconductor portion, the ohmic contacts forming an ohmic connection with the two-dimensional charge carrier gas. A gate structure is configured to control a conductive state of the two-dimensional charge carrier gas. Forming the one or more ohmic contacts comprises forming a structured laser-reflective mask on the upper surface of the type III-nitride semiconductor portion, implanting dopant atoms into the upper surface of the type III-nitride semiconductor portion, and performing a laser thermal anneal that activates the implanted dopant atoms.

A finFET device and methods of forming a finFET device are provided. The device includes a fin and a capping layer over the fin. The device also includes a gate stack over the fin, the gate stack including a gate electrode and a gate dielectric. The gate dielectric extends along sidewalls of the capping layer. The device further includes a gate spacer adjacent to sidewalls of the gate electrode, the capping layer being interposed between the gate spacer and the fin.

In some examples, a transistor includes a drain, a channel, and a gate. The channel surrounds the drain and has a channel length to width ratio. The gate is over the channel to provide an active channel region that has an active channel region length to width ratio that is greater than the channel length to width ratio.

A semiconductor device includes a first active structure on a substrate including a first epitaxial pattern, a second epitaxial pattern and a first channel pattern between the first epitaxial pattern and the second epitaxial pattern, the first channel pattern including at least one channel pattern stacked on the substrate. A first gate structure is disposed on top and bottom surfaces of the first channel pattern. A second active structure on the substrate and includes the second epitaxial pattern, a third epitaxial pattern and a second channel pattern between the second epitaxial pattern and the third epitaxial pattern in the first direction. The second channel pattern includes at least one channel pattern stacked on the substrate. The number of stacked second channel patterns is greater than the number of stacked first channel patterns. A second gate structure is disposed on top and bottom surfaces of the second channel pattern.

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.

Semiconductor device fabrication method is provided. The method includes providing a substrate; forming a first semiconductor layer on the substrate; forming a stack of semiconductor layer structures on the first semiconductor layer, each of the semiconductor layer structures comprising a second semiconductor layer and a third semiconductor layer on the second semiconductor layer, the second and third semiconductor layers having at least a common compound element, and the third semiconductor layer and the first semiconductor layer having a same semiconductor compound; performing an etching process to form a fin structure; performing a selective etching process on the second semiconductor layer to form a first air gap between the first semiconductor layer and the third semiconductor layer and a second air gap between each of adjacent third semiconductor layers in the stack of one or more semiconductor layer structures; and filling the first and second air gaps with an insulator layer.