According to one embodiment, a semiconductor device includes a first electrode, a second electrode, a third electrode, a first semiconductor layer, a second semiconductor layer, and a first insulating layer. A position of the third electrode in a first direction is between a position of the first electrode in the first direction and a position of the second electrode in the first direction. The first semiconductor layer includes Al.sub.x1Ga.sub.1-x1N and includes a first partial region, a second partial region, and a third partial region. The second semiconductor layer includes Al.sub.x2Ga.sub.1-x2N. A portion of the second semiconductor layer is between the third partial region and the third electrode in the second direction. The first insulating layer includes a first insulating region. The first insulating region is between the third electrode and the portion of the second semiconductor layer in the second direction.

A semiconductor device manufacturing method of embodiments includes: performing first ion implantation implanting an element of either carbon (C) or oxygen (O) into a nitride semiconductor layer; performing second ion implantation implanting hydrogen (H) into the nitride semiconductor layer; forming a coating layer on a surface of the nitride semiconductor layer; performing a first heat treatment; removing the coating layer; and performing a second heat treatment.

A semiconductor device manufacturing method of embodiments includes: performing first ion implantation implanting an element of either carbon (C) or oxygen (O) into a nitride semiconductor layer; performing second ion implantation implanting hydrogen (H) into the nitride semiconductor layer; forming a coating layer on a surface of the nitride semiconductor layer; performing a first heat treatment; removing the coating layer; and performing a second heat treatment.

Semiconductor devices and methods of forming the same are provided. A semiconductor device according to the present disclosure includes a ferroelectric structure including a channel region and a source/drain region, a gate dielectric layer disposed over the channel region of the ferroelectric structure, a gate electrode disposed on the gate dielectric layer, and a source/drain contact disposed on the source/drain region of the ferroelectric structure. The ferroelectric structure includes gallium nitride, indium nitride, or indium gallium nitride. The ferroelectric structure is doped with a dopant.

Semiconductor devices and methods of forming the same are provided. A semiconductor device according to the present disclosure includes a ferroelectric structure including a channel region and a source/drain region, a gate dielectric layer disposed over the channel region of the ferroelectric structure, a gate electrode disposed on the gate dielectric layer, and a source/drain contact disposed on the source/drain region of the ferroelectric structure. The ferroelectric structure includes gallium nitride, indium nitride, or indium gallium nitride. The ferroelectric structure is doped with a dopant.

A semiconductor structure includes a III-V compound layer, a first barrier layer, a second barrier layer, and an active layer. The III-V compound layer includes a first region, a second region, and a third region. The second region is sandwiched between the first region and the third region. The first barrier layer is sandwiched between the first region and the second region, and the second barrier layer is sandwiched between the second region and the third region. The III-V compound layer includes a first band gap, the first barrier layer includes a second band gap, and the second barrier layer includes a third band gap. The second band gap and the third band gap are greater than the first band gap.

A semiconductor structure includes a III-V compound layer, a first barrier layer, a second barrier layer, and an active layer. The III-V compound layer includes a first region, a second region, and a third region. The second region is sandwiched between the first region and the third region. The first barrier layer is sandwiched between the first region and the second region, and the second barrier layer is sandwiched between the second region and the third region. The III-V compound layer includes a first band gap, the first barrier layer includes a second band gap, and the second barrier layer includes a third band gap. The second band gap and the third band gap are greater than the first band gap.

Provided is a semiconductor substrate with a balance stress. The semiconductor substrate includes a ceramics base, a nucleation layer and a first buffer layer doped with a first dopant. The ceramics base has an off-cut angle other than 0 degree. The nucleation layer is disposed on the ceramics base. The first buffer layer is disposed on the nucleation layer. The first dopant includes C, Fe or a combination thereof. The first buffer layer provides compressive stress to the ceramic base. The concentration of the first dopant in the first buffer layer is increased away from the ceramics base. The curvature of the semiconductor substrate is between 16 km.sup.−1 and −16 km.sup.−1.

A semiconductor structure includes a buffer layer, a channel layer, a barrier layer, a doped compound semiconductor layer, and a composition gradient layer. The buffer layer is disposed on a substrate, the channel layer is disposed on the buffer layer, the barrier layer is disposed on the channel layer, the doped compound semiconductor layer is disposed on the barrier layer, and the composition gradient layer is disposed between the barrier layer and the doped compound semiconductor layer. The barrier layer and the composition gradient layer include a same group III element and a same group V element, and the atomic percentage of the same group III element in the composition gradient layer is gradually increased in the direction from the barrier layer to the doped compound semiconductor layer. A high electron mobility transistor and a fabrication method thereof are also provided.

A semiconductor structure includes a buffer layer, a channel layer, a barrier layer, a doped compound semiconductor layer, and a composition gradient layer. The buffer layer is disposed on a substrate, the channel layer is disposed on the buffer layer, the barrier layer is disposed on the channel layer, the doped compound semiconductor layer is disposed on the barrier layer, and the composition gradient layer is disposed between the barrier layer and the doped compound semiconductor layer. The barrier layer and the composition gradient layer include a same group III element and a same group V element, and the atomic percentage of the same group III element in the composition gradient layer is gradually increased in the direction from the barrier layer to the doped compound semiconductor layer. A high electron mobility transistor and a fabrication method thereof are also provided.