A semiconductor device includes a source region and a drain region formed in a transistor structure. A channel region is disposed between the source region and the drain region. A cladding layer is formed on the channel region, the cladding layer including a semiconductor material. A gate dielectric of a gate structure is formed on the cladding layer.

A method for fabricating semiconductor device includes the steps of first providing a substrate, forming a gate structure on the substrate, forming a hard mask on the substrate and the gate structure, patterning the hard mask to form trenches exposing part of the substrate, and forming raised epitaxial layers in the trenches. Preferably, the gate structure is extended along a first direction on the substrate and the raised epitaxial layers are elongated along a second direction adjacent to two sides of the gate structure.

A method for making a semiconductor device may include forming at least one double-barrier resonant tunneling diode (DBRTD) by forming a first doped semiconductor layer, and forming a first barrier layer on the first doped semiconductor layer and including a superlattice. The superlattice may include stacked groups of layers, each group of layers including stacked base semiconductor monolayers defining a base semiconductor portion, and at least one non-semiconductor monolayer constrained within a crystal lattice of adjacent base semiconductor portions. The method may further include forming an intrinsic semiconductor layer on the first barrier layer, forming a second barrier layer on the intrinsic semiconductor layer, and forming a second doped semiconductor layer on the second superlattice layer.

Transistor structures having channel regions comprising alternating layers of compressively and tensilely strained epitaxial materials are provided. The alternating epitaxial layers can form channel regions in single and mitigate transistor structures. In alternate embodiments, one of the two alternating layers is selectively etched away to form nanoribbons or nanowires of the remaining material. The resulting strained nanoribbons or nanowires form the channel regions of transistor structures. Also provided are computing devices comprising transistors comprising channel regions comprised of alternating compressively and tensilely strained epitaxial layers and computing devices comprising transistors comprising channel regions comprised of strained nanoribbons or nanowires.

A field effect transistor (FET) with an underlying airgap and methods of manufacture are disclosed. The method includes forming an amorphous layer at a predetermined depth of a substrate. The method further includes forming an airgap in the substrate under the amorphous layer. The method further includes forming a completely isolated transistor in an active region of the substrate, above the amorphous layer and the airgap.

A semiconductor device including at least one double-barrier resonant tunneling diode (DBRTD) is provided. The at least one DBRTD may include a first doped semiconductor layer, and a first barrier layer on the first doped semiconductor layer and including a superlattice. The DBRTD may further include a first intrinsic semiconductor layer on the first barrier layer, a second barrier layer on the first intrinsic semiconductor layer and also including the superlattice, a second intrinsic semiconductor layer on the second barrier layer, a third barrier layer on the second intrinsic semiconductor layer and also including the superlattice. A third intrinsic semiconductor layer may be on the third barrier layer, a fourth barrier layer may be on the third intrinsic semiconductor layer and also including the superlattice, a second doped semiconductor layer on the fourth barrier layer.

A method for making a semiconductor device may include forming at least one a double-barrier resonant tunneling diode (DBRTD) by forming a first doped semiconductor layer, and a forming first barrier layer on the first doped semiconductor layer and including a superlattice. The method may further include forming a first intrinsic semiconductor layer on the first barrier layer, forming a second barrier layer on the first intrinsic semiconductor layer and also comprising the superlattice, forming a second intrinsic semiconductor layer on the second barrier layer, and forming a third barrier layer on the second intrinsic semiconductor layer and also comprising the superlattice. The method may further include forming a third intrinsic semiconductor layer on the third barrier layer, forming a fourth barrier layer on the third intrinsic semiconductor layer, and forming a second doped semiconductor layer on the fourth barrier layer.

Semiconductor structures and devices including strained material layers having impurity-free zones, and methods for fabricating same. Certain regions of the strained material layers are kept free of impurities that can interdiffuse from adjacent portions of the semiconductor. When impurities are present in certain regions of the strained material layers, there is degradation in device performance. By employing semiconductor structures and devices (e.g., field effect transistors or FETs) that have the features described, or are fabricated in accordance with the steps described, device operation is enhanced.

A method of fabricating a device on a substrate includes doping a channel region of the device with dopants. The method further includes growing an undoped epitaxial layer over the channel region, wherein growing the undoped epitaxial layer comprises deactivating dopants in the channel region to form a deactivated region. The method further includes forming a gate structure over the deactivated region.

A metal-oxide-semiconductor field-effect transistor (MOSFET) device includes a channel region comprising dopants of a first type. The MOSFET device further includes a gate dielectric over the channel region, and a gate over the gate dielectric. The MOSFET device further includes a source comprising dopants of a second type, and a drain comprising dopants of the second type, wherein the channel region is between the source and the drain. The MOSFET device further includes a deactivated region underneath the gate, wherein dopants within the deactivated region are deactivated.