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 semiconductor structure also includes a S/D silicide layer formed on the S/D epitaxial layer, and the S/D silicide layer has a first width, the S/D epitaxial layer has a second width, and the first width is smaller than the second width. The semiconductor structure includes a dielectric spacer between the gate structure and the S/D silicide layer, and a top surface of the dielectric spacer is lower than a top surface of the gate structure.

In accordance with some embodiments, a source/drain contact is formed by exposing a source/drain region through a first dielectric layer and a second dielectric layer. The second dielectric layer is recessed under the first dielectric layer, and a silicide region is formed on the source/drain region, wherein the silicide region has an expanded width.

A method includes forming a fin protruding over a substrate; forming a conformal oxide layer over an upper surface and along sidewalls of the fin; performing an anisotropic oxide deposition or an anisotropic plasma treatment to form a non-conformal oxide layer over the upper surface and along the sidewalls of the fin; and forming a gate electrode over the fin, the conformal oxide layer and the non-conformal oxide layer being between the fin and the gate electrode.

An image sensor includes a photodiode disposed in a semiconductor substrate having a first surface and a second surface opposite to the first surface. A floating diffusion is disposed in the semiconductor substrate. A transfer transistor is configured for coupling the photodiode to the floating diffusion. The transfer transistor includes a vertical transfer gate extending a first depth in a depthwise direction from the first surface into the semiconductor substrate. A transistor is coupled to the floating diffusion. The transistor includes: a planar gate disposed proximate to the first surface of the semiconductor substrate; and a plurality of vertical gate electrodes, each extending a respective depth into the semiconductor substrate from the planar gate in the depthwise direction. The respective depth of at least one of the plurality of vertical gate electrodes is the same as the first depth of the vertical transfer gate.

An IC structure includes a plurality of first fins, a plurality of second fins, a plurality of first gate structures, a plurality of second gate structures, and a first gate contact. The first fins and the second fins are over a substrate. The first gate structures traverse the plurality of first fins. The second gate structures traverse the plurality of second fins. The first gate structures have a first gate pitch. The second gate structures have a second gate pitch wider than the first gate pitch. The first gate contact is over a first one of the second gate structures. The first gate contact overlaps a location where the first one of the second gate structures traverses across a first one of the second fins.

A method of manufacturing a semiconductor device is provided. The device includes a substrate including a first type region and a second type region, first and second fins protruding from the substrate and separated by a trench. The first fin includes first and second portions of the first type on the first region and a third portion of the second type on the second region. A first gate structure surrounds the second portion and the third portion. A first work function adjusting layer is on the gate insulator layer on the first and second portions. A second work function adjusting layer is on the first work function adjusting layer, the gate insulator layer on the third portion, and the first insulator layer. The device also includes a gate on the second work function adjusting layer, a hardmask layer on the gate, and an interlayer dielectric layer surrounding the gate structure.

A method of manufacturing a semiconductor device includes forming a first semiconductor layer on a substrate, forming a stack of semiconductor layer structures on the first semiconductor layer, and etching the stack to form a fin structure. Each of the semiconductor layer structures includes a first insulator layer and a second semiconductor layer on the first insulator layer. The first and second semiconductor layers have the same semiconductor compound. The fin structure according to the novel method includes one or more insulator layers to achieve a higher on current/off current ratio, thereby improving the device performance relative to conventional fin structures without the insulator layers.

A semiconductor device includes an insulating layer on a substrate, a first channel pattern on the insulating layer and contacting the insulating layer, second channel patterns on the first channel pattern and being horizontally spaced apart from each other, a gate pattern on the insulating layer and surrounding the second channel patterns, and a source/drain pattern between the second channel patterns.

In an embodiment, a device includes: a fin on a substrate, fin having a Si portion proximate the substrate and a SiGe portion distal the substrate; a gate stack over a channel region of the fin; a source/drain region adjacent the gate stack; a first doped region in the SiGe portion of the fin, the first doped region disposed between the channel region and the source/drain region, the first doped region having a uniform concentration of a dopant; and a second doped region in the SiGe portion of the fin, the second doped region disposed under the source/drain region, the second doped region having a graded concentration of the dopant decreasing in a direction extending from a top of the fin to a bottom of the fin.

A semiconductor structure is formed using a nanosheet stack that is over a semiconductor substrate. The semiconductor structure includes multiple layers of work function that surround each channel of a plurality of channels in the nanosheet stack and are on the semiconductor substrate under the nanosheet stack. Adjacent layers of the work function metal in the semiconductor structure are separated by an oxide material. The oxide material is a very thin layer of an oxide with a thickness of several angstroms or less. The semiconductor structure includes an n-type work function metal that is over an outer layer of the multiple layers of the work function metal. The n-type work function metal can be an aluminum containing metal that is covered by a capping material under a gate electrode material.