A semiconductor structure includes a source/drain region having a backside surface disposed in a backside interlayer dielectric layer, a backside contact disposed in the backside interlayer dielectric layer, wherein the backside contact is disposed on the backside surface of the source/drain region, backside sidewall spacers disposed between sidewalls of the backside interlayer dielectric layer and sidewalls of the backside contact and the backside surface of the source drain region, and a backside power rail connected to the source/drain region through the backside contact.

A semiconductor structure includes a stacked device structure having a first field-effect transistor having a first source/drain region, and a second field-effect transistor vertically stacked above the first field-effect transistor, the second field-effect transistor having a second source/drain region and a gate region having first sidewall spacers. The stacked device structure further includes a frontside source/drain contact disposed on a first portion of a sidewall and a top surface of the second source/drain region, a first metal via connected to the frontside source/drain contact and to a first backside power line, and second sidewall spacers disposed on a first portion of the first metal via. The first sidewall spacers comprise a first dielectric material and the second sidewall spacers comprise a second dielectric material different than the first dielectric material.

A semiconductor device includes: a channel having layers of silicon separated from each other; a metal gate in contact with the layers of silicon; source/drain regions adjacent to the metal gate; a frontside power rail extending through the layers of silicon; a dielectric separating the frontside power rail from the metal gate; a via-connect buried power rail extending through the dielectric and coupling the frontside power rail to the source/drain regions; and a backside power rail coupled to the frontside power rail. The layers of silicon are wrapped on three sides by the metal gate.

Three-dimensional (3D) NAND memory devices and methods are provided. In one aspect, a fabrication method includes forming a conductor/insulator stack over a substrate, configuring memory cells through the conductor/insulator stack, forming a conductive layer, removing a portion of the conductive layer to form an opening in the conductive layer, depositing a dielectric material in a space of the opening, and forming an airgap in the space.

Aspects of the present invention provide a semiconductor structure. The semiconductor structure may include a PFET source/drain (S/D). The PFET S/D may include a silicon germanium (SiGe)-based epi protruding through a BILD plane between a backside interlayer dielectric (BILD) and a first gate, and an NFET S/D. The NFET S/D may include a silicon (Si)-based epi protruding into the BILD plane and a SiGe epi between the BILD and the Si-based.

A semiconductor device includes a stacked transistor structure having field effect transistors on two levels. The two levels include a top side and a bottom side. Active regions are disposed on the bottom side including a leveled surface facing the top side and a faceted backside surface opposite the leveled surface. The leveled surface includes two different semiconductor materials. A backside contact in contact with the faceted backside surface forms a wraparound contact to reduce contact resistance.

In an embodiment, a device includes: a source/drain region over a semiconductor substrate; a dielectric layer over the source/drain region, the dielectric layer including a first dielectric material; an inter-layer dielectric over the dielectric layer, the inter-layer dielectric including a second dielectric material and an impurity, the second dielectric material different from the first dielectric material, a first portion of the inter-layer dielectric having a first concentration of the impurity, a second portion of the inter-layer dielectric having a second concentration of the impurity, the first concentration less than the second concentration; and a source/drain contact extending through the inter-layer dielectric and the dielectric layer to contact the source/drain region, the first portion of the inter-layer dielectric disposed between the source/drain contact and the second portion of the inter-layer dielectric.

A semiconductor structure includes a backside contact, and a source/drain region fully disposed within the backside contact.

Disclosed is a semiconductor device comprising an active region that protrudes upwardly from a substrate, a plurality of channel patterns that are spaced apart from each other in a first direction on the active region, and a gate electrode that extends in the first direction on the active region and covers the plurality of channel patterns. Each of the plurality of channel patterns includes a plurality of semiconductor patterns that are spaced apart from each other in a direction perpendicular to a top surface of the active region. The gate electrode covers the top surface of the active region between the plurality of channel patterns.

A method of forming a semiconductor device is provided. The method includes forming an etch stop layer on a substrate having a first thickness, forming an epitaxial layer on the etch stop layer, and forming a wafer device on the epitaxial layer. The wafer device is bonded to a bonding wafer using hybrid bonding. The substrate is then ground to a second thickness less than the first thickness and planarized to a third thickness less than the second thickness. A mask layer is deposited on a bottom surface of the etch stop layer, and at least one via opening is formed in the mask layer. The etch stop layer is selectively removed, and the mask layer is removed to expose the substrate at the third thickness.