A device includes a semiconductor substrate, a source feature and a drain feature over the semiconductor substrate, a stack of semiconductor layers interposed between the source feature and the drain feature, a gate portion, and an inner spacer of a dielectric material. The gate portion is between two vertically adjacent layers of the stack of semiconductor layers and between the source feature and the drain feature. Moreover, the gate portion has a first sidewall surface and a second sidewall surface opposing the first sidewall surface. The inner spacer is on the first sidewall surface and between the gate portion and the drain feature. The second sidewall surface is in direct contact with the source feature.

A high electron mobility transistor includes a stack of layers including a passivation layer and a heterojunction including a first semiconductor layer, a second semiconductor layer and a two-dimensional electron gas at the interface thereof, one surface of the passivation layer being in contact with the first semiconductor layer; a source metal contact and/or a drain metal contact and a gate electrode; an n+ doped zone situated inside the heterojunction; the source metal contact and/or the drain metal contact being positioned at the level of a recess formed in the stack of layers, the source metal contact and/or said drain metal contact having a thickness defined by an upper face and a lower face substantially parallel to the plane of the layers, the upper face being planar, the lower face being in contact with the n+ doped zone and below the interface between the first and second semiconductor layers.

Source/drain contacts between transistor gates with abbreviated inner spacers for improved contact area are disclosed. Related methods of fabricating source/drain contacts and abbreviated inner spacers are also disclosed. Inner spacers formed on sidewalls of the gates of adjacent transistors are abbreviated to reduce an amount of the space the inner spacers occupy on the source/drain region, increasing a critical dimension of the source/drain contact. Abbreviated inner spacers extend from a top of the gate over a portion of the sidewalls to provide leakage current protection but do not fully extend to the semiconductor substrate. As a result, the critical dimension of the source/drain contact can extend from a sidewall on a first gate to a sidewall on a second gate. A source/drain contact formed between gates with abbreviated inner spacers has a greater surface area in contact with the source/drain region providing decreased contact resistance.

Structures for suppressing parasitic acoustic waves in semiconductor structures and integrated circuit devices are described. Such integrated circuit devices can, typically, produce undesirable acoustic wave resonances, and the acoustic waves can degrade the performance of the devices. In that context, some embodiments described herein relate to spoiling a conductive path that participates in the generation of acoustic waves. Some embodiments relate to spoiling acoustic characteristics of an acoustic resonant structure that may be present in the vicinity of the device. Combined embodiments that spoil the conductive path and acoustic characteristics are also possible.

A method for fabricating high electron mobility transistor (HEMT) includes the steps of: forming a buffer layer on a substrate; forming a patterned mask on the buffer layer; using the patterned mask to remove the buffer layer for forming ridges and a damaged layer on the ridges; removing the damaged layer; forming a barrier layer on the ridges; and forming a p-type semiconductor layer on the barrier layer.

A semiconductor device includes a first nitride-based semiconductor layer, a second nitride-based semiconductor layer, a group of negatively-charged ions, and a field plate. The gate electrode and the drain electrode disposed above the second nitride-based semiconductor layer to define a drift region therebetween. The group of negatively-charged ions are implanted into the drift region and spaced apart from an area directly beneath the gate and drain electrodes to form at least one high resistivity zone in the second nitride-based semiconductor layer. The field plate is disposed over the gate electrode and extends in a region between the gate electrode and the high resistivity zone.

A tunnel field effect transistor includes a source region and a drain region, positioned on a substrate, a channel region positioned between the source region and the drain region and having a first length in a first direction, a gate electrode positioned on the channel region, and a gate insulating layer positioned between the channel region and the gate electrode, wherein the source region is doped with impurities of a first conductivity type and the drain region is doped with impurities of a second conductivity type that is different from the first conductivity type, and one of the source region and the drain region includes an extension region extending toward the other region, the extension region being positioned under the channel region to form a constant current independent of a gate voltage of the gate electrode.

A semiconductor device includes a carrier generation layer disposed on a channel layer, a source contact and a drain contact disposed on the carrier generation layer, and a gate contact disposed between the source contact and the drain contact. The semiconductor device further includes a number N of conductive stripes disposed directly on the carrier generation layer in an area between the drain contact and the gate contact, and a number M of conductive transverse stripes disposed directly on the carrier generation layer in the area between the drain contact and the gate contact. Each of the N conductive stripes extends from and is electrically coupled to the drain contact. Each of the M conductive transverse stripes is aligned non-parallel to the N conductive stripes and is not in direct physical contact with the N conductive stripes.

A semiconductor device according to one aspect of the present disclosure includes a substrate including a first main surface, a semiconductor layer provided on the first main surface of the substrate, and a gate electrode, a source electrode, and a drain electrode, provided on the semiconductor layer. The semiconductor layer has an electron transit layer provided above the substrate and including a first upper surface, and an electron supply layer provided above the electron transit layer. The electron supply layer and the electron transit layer have a first opening and a second opening. A bottom surface of the first opening and a bottom surface of the second opening each exist at a deeper position toward the substrate than the first upper surface.

The present disclosure relates to a semiconductor device and a fabrication method thereof. The semiconductor device includes a substrate, a first nitride semiconductor layer on the substrate and a second nitride semiconductor layer on the first nitride semiconductor layer. The second nitride semiconductor layer has a first area and a second area, and the second nitride semiconductor layer has single crystals. The semiconductor device includes an electrode in contact with the first area. A first concentration of Aluminum (Al) of the first area is less than a second concentration of Al of the second area, and the single crystals in the first area take over a crystal structure of the first nitride semiconductor layer.