Epitaxial regions may be formed in specific locations on a semiconductor wafer with specific asymmetric properties such as slope or tilt direction, slope or tilt angle, and/or other asymmetric properties. The asymmetric epitaxial regions may be formed using various plasma-based fin structure etching techniques described herein. The specific asymmetric properties may increase metal landing coverage areas in particular locations on the semiconductor wafer (e.g., that are optimized for particular locations on the semiconductor substrate) to reduce the contact resistance between the epitaxial regions and associated conductive structures that are formed to the epitaxial regions. This increases semiconductor device performance, decreases the rate and/or likelihood of defect formation, and/or increases semiconductor device yield, among other examples.

A method includes etching a semiconductor substrate to form a trench between a first semiconductor strip and a second semiconductor strip. The first semiconductor strip has a first width at about 5 nm below a top of the first semiconductor strip and a second width at about 60 nm below the top of the first semiconductor strip. The first width is smaller than about 5 nm, and the second width is smaller than about 14.5 nm. The trench is filled with dielectric materials to form an isolation region, which is recessed to have a depth. A top portion of the first semiconductor strip protrudes higher than the isolation region to form a protruding fin. The protruding fin has a height smaller than the depth. A gate stack is formed to extend on a sidewall and a top surface of the protruding fin.

A method includes removing a first dummy gate stack and a second dummy gate stack to form a first trench and a second trench. The first dummy gate stack and the second dummy gate stack are in a first device region and a second device region, respectively. The method further includes depositing a first gate dielectric layer and a second gate dielectric layer extending into the first trench and the second trench, respectively, forming a fluorine-containing layer comprising a first portion over the first gate dielectric layer, and a second portion over the second gate dielectric layer, removing the second portion, performing an annealing process to diffuse fluorine in the first portion into the first gate dielectric layer, and at a time after the annealing process, forming a first work-function layer and a second work-function layer over the first gate dielectric layer and the second gate dielectric layer, respectively.

A semiconductor device according to the present disclosure includes a stack of first channel members, a stack of second channel members disposed directly over the stack of first channel members, a bottom source/drain feature in contact with the stack of the first channel members, a separation layer disposed over the bottom source/drain feature, a top source/drain feature in contact with the stack of second channel members and disposed over the separation layer, and a frontside contact that extends through the top source/drain feature and the separation layer to be electrically coupled to the bottom source/drain feature.

An integrated circuit includes a nanosheet transistor having a plurality of stacked channels, a gate electrode surrounding the stacked channels, a source/drain region, and a source/drain contact. The integrated circuit includes a first dielectric layer between the gate metal and the source/drain contact, a second dielectric layer on the first dielectric layer, and a cap metal on the first gate metal and on a hybrid fin structure. The second dielectric layer is on the hybrid fin structure between the cap metal and the source/drain contact.

Confined epitaxial regions for semiconductor devices and methods of fabricating semiconductor devices having confined epitaxial regions are described. For example, a semiconductor structure includes a plurality of parallel semiconductor fins disposed above and continuous with a semiconductor substrate. An isolation structure is disposed above the semiconductor substrate and adjacent to lower portions of each of the plurality of parallel semiconductor fins. An upper portion of each of the plurality of parallel semiconductor fins protrudes above an uppermost surface of the isolation structure. Epitaxial source and drain regions are disposed in each of the plurality of parallel semiconductor fins adjacent to a channel region in the upper portion of the semiconductor fin. The epitaxial source and drain regions do not extend laterally over the isolation structure. The semiconductor structure also includes one or more gate electrodes, each gate electrode disposed over the channel region of one or more of the plurality of parallel semiconductor fins.

The present disclosure relates to a semiconductor structure that includes a well region and a semiconductor substrate. The well region is disposed within the semiconductor substrate. The well region includes a plurality of first regions separated by a plurality of second regions, where the plurality of first regions is of a first doping and the plurality of second regions are of a second doping different than the first doping. A gate electrode overlies the well region where the gate electrode is disposed laterally over a portion of the plurality of first regions and a portion of the plurality of second regions.

A method of manufacturing a parallel structure of semiconductor devices includes: disposing a semiconductor stack, which includes source/drain layers disposed vertically in sequence and channel layers therebetween, on a substrate; patterning the semiconductor stack into a predetermined shape to define an active region; forming gate stacks around at least part of peripheries of the channel layers; forming an isolation layer on peripheries of the active region and the gate stack; forming first to third conductive channels on a sidewall of the isolation layer; determining the pre-determined shape and a shape of the gate stacks, such that one of the source/drain layers on two sides of the channel layer passes through the isolation layer to contact the first conductive channel, while the other one passes through the isolation layer to contact the second conductive channel, and the gate stack passes through the isolation layer to contact the third conductive channel.

A method includes depositing a silicon layer, which includes first portions over a plurality of strips, and second portions filled into trenches between the plurality of strips. The plurality of strips protrudes higher than a base structure. The method further includes performing an anneal to allow parts of the first portions of the silicon layer to migrate toward lower parts of the plurality of trenches, and performing an etching on the silicon layer to remove some portions of the silicon layer.

A method for forming a semiconductor device structure is provided. The semiconductor device includes forming nanowire structures stacked over a substrate and spaced apart from one another, and forming a dielectric material surrounding the nanowire structures. The dielectric material has a first nitrogen concentration. The method also includes treating the dielectric material to form a treated portion. The treated portion of the dielectric material has a second nitrogen concentration that is greater than the first nitrogen concentration. The method also includes removing the treating portion of the dielectric material, thereby remaining an untreated portion of the dielectric material as inner spacer layers; and forming the gate stack surrounding nanowire structures and between the inner spacer layers.