Contact over active gate (COAG) structures with conductive gate taps are described. In an example, an integrated circuit structure includes a plurality of gate structures above a substrate, each of the gate structures including a gate insulating layer thereon. Each of the plurality of gate structures includes a conductive tap structure protruding through the corresponding gate insulating layer. A plurality of conductive trench contact structures is alternating with the plurality of gate structures, each of the conductive trench contact structures including a trench insulating layer thereon. An interlayer dielectric material is above the trench insulating layers and the gate insulating layers. An opening is in the interlayer dielectric material and exposes the conductive tap structure of one of the plurality of gate structures. A conductive structure is in the opening and is in direct contact with the conductive tap structure of one of the plurality of gate structures.

Semiconductor device and the manufacturing method thereof are disclosed. An exemplary method of manufacture comprises receiving a substrate including a semiconductor material stack formed thereon, wherein the semiconductor material stack includes a first semiconductor layer of a first semiconductor material and second semiconductor layer of a second semiconductor material that is different than the first semiconductor material. Patterning the semiconductor material stack to form a trench. The patterning includes performing a first etch process with a first etchant for a first duration and then performing a second etch process with a second etchant for a second duration, where the second etchant is different from the first etchant and the second duration is greater than the first duration. The first etch process and the second etch process are repeated a number of times. Then epitaxially growing a third semiconductor layer of the first semiconductor material on a sidewall of the trench.

Embodiments of mechanisms for forming dislocations in source and drain regions of finFET devices are provided. The mechanisms involve recessing fins and removing the dielectric material in the isolation structures neighboring fins to increase epitaxial regions for dislocation formation. The mechanisms also involve performing a pre-amorphous implantation (PAI) process either before or after the epitaxial growth in the recessed source and drain regions. An anneal process after the PAI process enables consistent growth of the dislocations in the source and drain regions. The dislocations in the source and drain regions (or stressor regions) can form consistently to produce targeted strain in the source and drain regions to improve carrier mobility and device performance for NMOS devices.

Semiconductor device fabrication method is provided. The method includes providing a substrate; forming a first semiconductor layer on the substrate; forming a stack of semiconductor layer structures on the first semiconductor layer, each of the semiconductor layer structures comprising a second semiconductor layer and a third semiconductor layer on the second semiconductor layer, the second and third semiconductor layers having at least a common compound element, and the third semiconductor layer and the first semiconductor layer having a same semiconductor compound; performing an etching process to form a fin structure; performing a selective etching process on the second semiconductor layer to form a first air gap between the first semiconductor layer and the third semiconductor layer and a second air gap between each of adjacent third semiconductor layers in the stack of one or more semiconductor layer structures; and filling the first and second air gaps with an insulator layer.

An improvement is achieved in the reliability of a semiconductor device. In a memory cell region, a plurality of fins are provided which are portions of a semiconductor substrate extending in an x-direction along a main surface of the semiconductor substrate and spaced apart from each other in a y-direction orthogonal to the x-direction along the main surface of the semiconductor substrate. Between the fins adjacent to each other in the y-direction, a portion of an upper surface of an isolation region is at a position higher than a surface obtained by connecting a position of the upper surface of the isolation region which is in contact with a side wall of one of the fins to a position of the upper surface of the isolation region which is in contact with a side wall of the other fin. In a cross section along the y-direction, the upper surface of the isolation region has a projecting shape.

A method for fabricating semiconductor device includes: forming a first semiconductor layer and an insulating layer on a substrate; removing the insulating layer and the first semiconductor layer to form openings; forming a second semiconductor layer in the openings; and patterning the second semiconductor layer, the insulating layer, and the first semiconductor layer to form fin-shaped structures.

A semiconductor device includes a substrate, at least one active region, at least one gate structure, and an insulating structure. The active region is present at least partially in the substrate. The gate structure is present on the active region. The gate structure has at least one end sidewall and a top surface intersecting to form a top interior angle. The top interior angle is an acute angle. The insulating structure is present adjacent to the end sidewall of the gate structure and on the substrate.

A semiconductor device includes an active region spanning along a first direction. The semiconductor device includes a first elongated gate spanning along a second direction substantially perpendicular to the first direction. The first elongated gate includes a first portion that is disposed over the active region and a second portion that is not disposed over the active region. The first portion and the second portion include different materials. The semiconductor device includes a second elongated gate spanning along the second direction and separated from the first elongated gate in the first direction. The second elongated gate includes a third portion that is disposed over the active region and a fourth portion that is not disposed over the active region. The third portion and the fourth portion include different materials.

A semiconductor structure and a method for forming the same are provided. The semiconductor structure includes a gate structure formed over a fin structure, and a source/drain (S/D) epitaxial layer formed in the fin structure and adjacent to the gate structure. The S/D epitaxial layer includes a first S/D epitaxial layer and a second epitaxial layer. The semiconductor structure includes a gate spacer formed on a sidewall surface of the gate structure, and the gate spacer is directly over the first S/D epitaxial layer. The semiconductor structure includes a dielectric spacer formed adjacent to the gate spacer, and the dielectric spacer is directly over the second epitaxial layer.

Disclosed herein are field-effect transistors with asymmetric gate stacks. An example transistor includes a channel material and an asymmetric gate stack, provided over a portion of the channel material between source and drain (S/D) regions. The gate stack is asymmetric in that a thickness of a gate dielectric of a portion of the gate stack closer to one of the S/D regions is different from that of a portion of the gate stack closer to the other S/D region, and in that a work function (WF) material of a portion of the gate stack closer to one of the S/D regions is different from a WF material of a portion of the gate stack closer to the other S/D region. Transistors as described herein exploit asymmetry in the gate stacks to improve the transistor performance in terms of high breakdown voltage, high gain, and/or high output resistance.