A semiconductor device including a transistor having a minute size is provided. In the semiconductor device, a second conductive layer is provided over a first conductive layer; the second conductive layer has a first opening overlapping with the first conductive layer; a third conductive layer is provided over the second conductive layer; the third conductive layer has a second opening overlapping with the first opening; a first insulating layer is in contact with a sidewall of the first opening in the second conductive layer; a semiconductor layer is in contact with a top surface of the first conductive layer, a side surface of the first insulating layer, and a top surface of the third conductive layer; a second insulating layer is provided over the semiconductor layer; a fourth conductive layer is provided over the second insulating layer; the first insulating layer includes a region sandwiched between the sidewall of the first opening in the second conductive layer and the semiconductor layer; and the semiconductor layer includes a region sandwiched between the sidewall of the first opening in the second conductive layer and the fourth conductive layer.

A semiconductor device and a manufacturing method thereof are provided. The semiconductor device includes a semiconductor substrate, semiconductor nanosheets vertically stacked upon one another and disposed above the semiconductor substrate, a gate structure surrounding each of the semiconductor nanosheets, inner spacers laterally covering the gate structure and interposed between the semiconductor nanosheets, and source/drain (S/D) regions disposed over the semiconductor substrate and laterally abutting the semiconductor nanosheets. The semiconductor nanosheets serve as channel regions. A bottommost inner spacer of the inner spacers underlying a bottommost semiconductor nanosheet of the semiconductor nanosheets is thinner than a topmost inner spacer of the inner spacers underlying a topmost semiconductor nanosheet of the semiconductor nanosheets. The S/D regions are separated from the gate structure through the inner spacers.

Semiconductor device and the manufacturing method thereof are disclosed. An exemplary method comprises forming a first stack structure and a second stack structure in a first area over a substrate, wherein each of the stack structures includes semiconductor layers separated and stacked up; depositing a first interfacial layer around each of the semiconductor layers of the stack structures; depositing a gate dielectric layer around the first interfacial layer; forming a dipole oxide layer around the gate dielectric layer; removing the dipole oxide layer around the gate dielectric layer of the second stack structure; performing an annealing process to form a dipole gate dielectric layer for the first stack structure and a non-dipole gate dielectric layer for the second stack structure; and depositing a first gate electrode around the dipole gate dielectric layer of the first stack structure and the non-dipole gate dielectric layer of the second stack structure.

A transistor with small parasitic capacitance can be provided. A transistor with high frequency characteristics can be provided. A semiconductor device including the transistor can be provided. Provided is a transistor including an oxide semiconductor, a first conductor, a second conductor, a third conductor, a first insulator, and a second insulator. The first conductor has a first region where the first conductor overlaps with the oxide semiconductor with the first insulator positioned therebetween; a second region where the first conductor overlaps with the second conductor with the first and second insulators positioned therebetween; and a third region where the first conductor overlaps with the third conductor with the first and second insulators positioned therebetween. The oxide semiconductor including a fourth region where the oxide semiconductor is in contact with the second conductor; and a fifth region where the oxide semiconductor is in contact with the third conductor.

A semiconductor device includes thin film transistors each having an oxide semiconductor. The oxide semiconductor has a channel region, a drain region, a source region, and low concentration regions which are lower in impurity concentration than the drain region and the source region. The low concentration regions are located between the channel region and the drain region, and between the channel region and the source region. Each of the thin film transistors has a gate insulating film on the channel region and the low concentration regions, an aluminum oxide film on a first part of the gate insulating film, the first part being located on the channel region, and a gate electrode on the aluminum oxide film and a second part of the gate insulating film, the second part being located on the low concentration regions.

Provided is an oxide semiconductor thin film transistor with low parasitic capacitance and high reliability. A thin film transistor includes a substrate, an oxide semiconductor layer including a channel region, a source region, and a drain region, a gate insulating film, and a gate electrode. The gate insulating film includes one layer or two layers, at least one of the layers of the gate insulating film is a patterned gate insulating film located at a position separated from the source electrode and the drain electrode. A length of a lower surface of the patterned gate insulating film in a channel length direction is greater than a length of a lower surface of the gate electrode in the channel length direction. The length of the lower surface of the patterned gate insulating film in the channel length direction is greater than a length of the channel region in the channel length direction. The source region and the drain region have a higher hydrogen concentration than the channel region.

The present invention provides a field effect transistor and the method for preparing such a filed effect transistor. The filed effect transistor comprises a semiconductor, germanium nanowires, a first III-V compound layer surrounding the germanium nanowires, a semiconductor barrier layer, a gate dielectric layer and a gate electrode sequentially formed surrounding the first III-V compound layer, and source/drain electrodes are respectively located at each side of the gate electrode and on the first III-V compound layer. According to the present invention, the band width of the barrier layer is greater than that of the first III-V compound layer, and the band curvatures of the barrier layer and the first III-V compound layer are different, therefore, a two-dimensional electron gas (2DEG) is formed in the first III-V compound layer near the barrier layer boundary. Since the 2DEG has higher mobility, the performance of the filed effect transistor improved. Besides, the performance of the filed effect transistor also improved due to the structure is a gate-all-around structure.

A semiconductor device includes a first insulating layer having a first side wall, an oxide semiconductor layer located on the first side wall, a gate insulating layer located on the oxide semiconductor layer, the oxide semiconductor layer being located between the first side wall and the gate insulating layer, a gate electrode facing the oxide semiconductor layer located on the first side wall, the gate insulating layer being located between the oxide semiconductor layer and the gate electrode, a first electrode located below the oxide semiconductor layer and connected with one portion of the oxide semiconductor layer, and a second electrode located above the oxide semiconductor layer and connected with the other portion of the oxide semiconductor layer.

Methods for forming a transistor include forming a gate conductor in contact with a gate stack. The gate conductor has a top surface that meets a middle point of sidewalls of a sacrificial region of a fin. The sacrificial region of the fin is trimmed to create gaps above the gate stack. A top spacer is formed on the gate conductor. The top spacer includes airgaps above the gate stack.

A transistor includes a vertical channel fin directly on a bottom source/drain region. A gate stack is formed on sidewalls of the vertical channel fin. A top spacer is formed over the gate stack. The top spacer has air gaps directly above the gate stack. A top source/drain region is formed directly on a top surface of the vertical channel fin.