A semiconductor device including an insulating layer on a substrate; channel semiconductor patterns stacked on the insulating layer and vertically spaced apart from each other; a gate electrode crossing the channel semiconductor patterns; source/drain regions respectively at both sides of the gate electrode and connected to each other through the channel semiconductor patterns, the source/drain regions having concave bottom surfaces; and air gaps between the insulating layer and the bottom surfaces of the source/drain regions.

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.

Describe is a resonator that uses ferroelectric (FE) materials in the gate of a transistor as a dielectric. The use of FE increases the strain/stress generated in the gate of the FinFET. Along with the usual capacitive drive, which is boosted with the increased polarization, FE material expands or contacts depending on the applied electric field on the gate of the transistor. As such, acoustic waves are generated by switching polarization of the FE materials. In some embodiments, the acoustic mode of the resonator is isolated using phononic gratings all around the resonator using the metal line above and vias' to body and dummy fins on the side. As such, a Bragg reflector is formed above the FE based transistor.

A transistor whose channel region includes an oxide semiconductor is used as a pull down transistor. The band gap of the oxide semiconductor is 2.0 eV or more, preferably 2.5 eV or more, more preferably 3.0 eV or more. Thus, hot carrier degradation in the transistor can be suppressed. Accordingly, the circuit size of the semiconductor device including the pull down transistor can be made small. Further, a gate of a pull up transistor is made to be in a floating state by switching of onion of the transistor whose channel region includes an oxide semiconductor. Note that when the oxide semiconductor is highly purified, the off-state current of the transistor can be 1 aA/μm (1×10.sup.−18 A/μm) or less. Therefore, the drive capability of the semiconductor device can be improved.

A lateral diffusion metal oxide semiconductor (LDMOS) device includes a first fin-shaped structure on a substrate, a shallow trench isolation (STI) adjacent to the first fin-shaped structure, a first gate structure on the first fin-shaped structure, a spacer adjacent to the first gate structure, and a contact field plate adjacent to the first gate structure and directly on the STI. Preferably, a sidewall of the spacer is aligned with a sidewall of the first fin-shaped structure.

It is an object to provide a highly reliable semiconductor device including a thin film transistor with stable electric characteristics. In a semiconductor device including an inverted staggered thin film transistor whose semiconductor layer is an oxide semiconductor layer, a buffer layer is provided over the oxide semiconductor layer. The buffer layer is in contact with a channel formation region of the semiconductor layer and source and drain electrode layers. A film of the buffer layer has resistance distribution. A region provided over the channel formation region of the semiconductor layer has lower electrical conductivity than the channel formation region of the semiconductor layer, and a region in contact with the source and drain electrode layers has higher electrical conductivity than the channel formation region of the semiconductor layer.

According to one embodiment, a semiconductor device includes first, second, third nitride members, first, second, third electrodes, and a first insulating member. The first nitride member includes a first face along a first plane, a second face along the first plane, and a third face. The third face is connected with the first and second faces between the first and second faces. The third face crosses the first plane. The first face overlaps a part of the first nitride member. The second nitride member includes a first nitride region provided at the first face. The third nitride member includes a first nitride portion provided at the second face. The first electrode includes a first connecting portion. The second electrode includes a second connecting portion. The third electrode includes a first electrode portion. The first insulating member includes a first insulating region.

A method for forming a transistor structure includes steps as follows: A substrate with an original surface is prepared. Next a gate conductive region is formed, wherein at least a portion of the gate conductive region is disposed below the original surface, and a bottom wall and sidewalls of the gate conductive region is surrounded by a gate dielectric layer. Then, a first conductive region is formed, wherein a bottom wall of the first conductive region is aligned or substantially aligned with a top wall of the gate conductive region.

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.

As a display device has a higher definition, the number of pixels, gate lines, and signal lines are increased. When the number of the gate lines and the signal lines are increased, a problem of high manufacturing cost, because it is difficult to mount an IC chip including a driver circuit for driving of the gate and signal lines by bonding or the like. A pixel portion and a driver circuit for driving the pixel portion are provided over the same substrate, and at least part of the driver circuit includes a thin film transistor using an oxide semiconductor interposed between gate electrodes provided above and below the oxide semiconductor. Therefore, when the pixel portion and the driver portion are provided over the same substrate, manufacturing cost can be reduced.