A JFET structure may be formed such that the channel region is isolated from the substrate to reduce parasitic capacitance. For example, instead of using a deep well as part of a gate structure for the JFET, the deep well may be used as an isolation region from the surrounding substrate. As a result, the channel in the JFET may be pinched laterally between doped regions located between the source and the drain of the JFET. In other example embodiments, the channel may be pinched vertically and the isolation between the JFET structure and the substrate is maintained. A JFET structure with improved isolation from the substrate may be employed in some embodiments as a low-noise amplifier. In particular, the low-noise amplifier may be coupled to small signal devices, such as microelectromechanical systems (MEMS)-based microphones.

A method of forming a semiconductor device that may include etching source and drain portions of a fin structure of a first semiconductor material selectively to an underlying semiconductor layer of a second semiconductor material, and laterally etching undercut region in the semiconductor layer underlying the fin structure. The method may further include filling the undercut region with a first conductivity type semiconductor material, and forming a second conductivity type semiconductor material for a source region and a drain region on opposing sides of the channel region portion of the fin structure.

An integrated circuit contains a logic MOS transistor and a memory MOS transistor of a same polarity. The logic MOS transistor has a logic channel stop layer. The memory MOS transistor has a memory channel stop layer. An average dopant density of the memory channel stop layer is higher than an average dopant density of the logic channel stop layer. The integrated circuit is formed by forming a global mask which exposes both the logic and memory MOS transistors. A global channel stop dose of dopants is implanted in the logic and memory MOS transistors. A memory mask is formed which exposes the memory MOS transistor and covers the logic MOS transistor. A memory channel stop dose of dopants of the same polarity is implanted into the memory MOS transistors. The memory channel stop dose of dopants are blocked from the logic MOS transistors.

There is provided a semiconductor device having LDMOS transistors embedded in a semiconductor substrate to boost source-drain breakdown voltage, with arrangements to prevent fluctuations of element characteristics caused by electric field concentration so that the reliability of the semiconductor device is improved. A trench is formed over the upper surface of a separation insulating film of each LDMOS transistor, the trench having a gate electrode partially embedded therein. This structure prevents electric field concentration in the semiconductor substrate near the source-side edge of the separation insulating film.

A method of forming a punch through stop region in a fin structure is disclosed. The method may include forming a doped glass layer on a fin structure and forming a masking layer on the doped glass layer. The method may further include removing a portion of the masking layer from an active portion of the fin structure, and removing an exposed portion the doped glass layer that is present on the active portion of the fin structure. A remaining portion of the doped glass layer is present on the isolation portion of the fin structure. Dopant from the doped glass layer may then be diffused into the isolation portion of the fin structure to form the punch through stop region between the active portion of the fin structure and a supporting substrate.

A fin-type field effect transistor comprising a substrate, a plurality of insulators, at least one gate stack and strained material portions is described. The substrate has a plurality of fins thereon and the fin comprises a stop layer embedded therein. The plurality of insulators is disposed on the substrate and between the plurality of fins. The at least one gate stack is disposed over the plurality of fins and on the plurality of insulators. The strained material portions are disposed on two opposite sides of the at least one gate stack.

Digital circuits are disclosed that may include multiple transistors having controllable current paths coupled between first and second logic nodes. One or more of the transistors may have a deeply depleted channel formed below its gate that includes a substantially undoped channel region formed over a relatively highly doped screen layer formed over a doped body region. Resulting reductions in threshold voltage variation may improve digital circuit performance. Logic circuit, static random access memory (SRAM) cell, and passgate embodiments are disclosed.

First and second transistors with different electrical characteristics are supported by a substrate having a first-type dopant. The first transistor includes a well region within the substrate having the first-type dopant, a first body region within the well region having a second-type dopant and a first source region within the first body region and laterally offset from the well region by a first channel. The second transistor includes a second body region within the semiconductor substrate layer having the second-type dopant and a second source region within the second body region and laterally offset from material of the substrate by a second channel having a length greater than the length of the first channel. A gate region extends over portions of the first and second body regions for the first and second channels, respectively.

A semiconductor die that may include a substrate; an epitaxial layer; a metal layer; a first transistor; and a metal via that surrounds the first transistor, extends between the metal layer and the substrate, and penetrates the substrate.

The characteristics of a semiconductor device are improved. A semiconductor device has a potential fixed layer containing a p type impurity, a channel layer, and a barrier layer, formed over a substrate, and a gate electrode arranged in a trench penetrating through the barrier layer, and reaching some point of the channel layer via a gate insulation film. Source and drain electrodes are formed on opposite sides of the gate electrode. The p type impurity-containing potential fixed layer has an inactivated region containing an inactivating element such as hydrogen between the gate and drain electrodes. Thus, while raising the p type impurity (acceptor) concentration of the potential fixed layer on the source electrode side, the p type impurity of the potential fixed layer is inactivated on the drain electrode side. This can improve the drain-side breakdown voltage while providing a removing effect of electric charges by the p type impurity.