Embodiments of bonded unified semiconductor chips and fabrication and operation methods thereof are disclosed. In an example, a method for forming a unified semiconductor chip is disclosed. A first semiconductor structure is formed. The first semiconductor structure includes one or more processors, an array of embedded DRAM cells, and a first bonding layer including a plurality of first bonding contacts. A second semiconductor structure is formed. The second semiconductor structure includes an array of NAND memory cells and a second bonding layer including a plurality of second bonding contacts. The first semiconductor structure and the second semiconductor structure are bonded in a face-to-face manner, such that the first bonding contacts are in contact with the second bonding contacts at a bonding interface.

A thin film transistor includes an active layer located over a substrate, a first gate stack including a stack of a first gate dielectric and a first gate electrode and located on a first surface of the active layer, a pair of first contact electrodes contacting peripheral portions of the first surface of the active layer and laterally spaced from each other along a first horizontal direction by the first gate electrode, a second contact electrode contacting a second surface of the active layer that is vertically spaced from the first surface of the active layer, and a pair of second gate stacks including a respective stack of a second gate dielectric and a second gate electrode and located on a respective peripheral portion of a second surface of the active layer.

A semiconductor device, the device including: a first silicon layer including a first single crystal silicon layer and a plurality of first transistors; a first metal layer disposed over the first single crystal silicon layer; a second metal layer disposed over the first metal layer; a third metal layer disposed over the second metal layer; a second level including a plurality of second transistors, the second level disposed over the third metal layer; a fourth metal layer disposed over the second level; a fifth metal layer disposed over the fourth metal layer; and a via disposed through the second level, where the via has a diameter of less than 450 nm, where the via includes tungsten, and where a typical thickness of the fifth metal layer is greater than a typical thickness of the second metal layer by at least 50%.

In certain aspects, a memory device includes a memory cell including a vertical transistor, and a storage unit having a first end coupled to a first terminal of the vertical transistor. The vertical transistor includes a semiconductor body extending in a first direction, and a gate structure coupled to at least one side of the semiconductor body. The memory device also includes a metal bit line coupled to a second terminal of the vertical transistor via an ohmic contact and extending in a second direction perpendicular to the first direction. The memory device further includes a dielectric layer opposing the memory cell with the metal bit line positioned between the dielectric layer and the memory cell. The memory device further includes a conductor extending from the dielectric layer to couple to a second end of the storage unit.

A CFET includes a fin that has a bottom channel portion, a top channel portion, and a channel isolator between the bottom channel portion and the top channel portion. The CFET further includes a source and drain stack that has a bottom source or drain (S/D) region connected to the bottom channel portion, a top S/D region connected to the top channel portion, a source-drain isolator between the bottom S/D region and the top S/D region. The CFET further includes a spacer foot physically connected to a base sidewall portion of the bottom S/D region and a buried S/D contact that is physically connected to an upper sidewall portion of the bottom S/D region. The CFET may further include a common gate around the bottom channel portion, around the top channel portion, and around the channel isolator.

A method of fabricating a semiconductor device is provided. An initial stack of layers is formed over a substrate. The initial stack alternates between a first material layer and a second material layer that has a different composition from the first material layer. The initial stack is divided into a first stack and a second stack. First GAA transistors are formed in the first stack by using the first material layers as respective channel regions for the first GAA transistors and using the second material layers as respective replacement gates for the first GAA transistors. Second GAA transistors are formed in the second stack by using the second material layers as respective channel regions for the second GAA transistors and using the first material layers as respective replacement gates for the second GAA transistors. The second GAA transistors are vertically offset from the first GAA transistors.

A semiconductor device including: a first silicon layer including a first single crystal silicon and a plurality of first transistors; a first metal layer disposed over the first silicon layer; a second metal layer disposed over the first metal layer; a third metal layer disposed over the second metal layer; a second level including a plurality of second transistors, the second level disposed over the third metal layer; a fourth metal layer disposed over the second level; a fifth metal layer disposed over the fourth metal layer, where the fourth metal layer is aligned to first metal layer with a less than 40 nm alignment error; and a via disposed through the second level, where each of the second transistors includes a metal gate, and where a typical thickness of the second metal layer is greater than a typical thickness of the third metal layer by at least 50%.

Integrated circuit (IC) devices implementing bilayer memory stacking with compute logic circuits shared between bottom and top memory layers are disclosed. An example IC device includes a first IC structure that includes one or more memory layers but not necessarily compute logic circuits, the first IC structure being bonded with a second IC structure that includes at least one layer of compute logic circuits and further includes one or more memory layers stacked above the compute logic circuits. The first and second IC structures may be bonded so that the compute logic circuits of the second IC structure may be communicatively coupled to memory layers of both the first and second IC structures.

A stacked FET structure having independently tuned gate lengths is provided to maximize the benefit of each FET within the stacked FET structure. Notably, a vertically stacked FET structure is provided in which a bottom FET has a different gate length than a top FET. In some embodiments, a dielectric spacer can be present laterally adjacent to the bottom FET and the top FET. In such an embodiment, the dielectric spacer can have a first portion that is located laterally adjacent to the bottom FET that has a different thickness than a second portion of the dielectric spacer that is located laterally adjacent the top FET.

The solution provides a device formed in a layer stack that includes a source contact layer and a gate contact layer with a first insulation between the gate contact layer and the source contact layer and a drain contact layer with a second insulation between the gate contact layer and the drain contact layer. The layer stack can include a device region orthogonal to a plane defined by a surface of at least one of the layers of the stack. The device region includes a source and a drain separated by a channel at least partially surrounded by a gate dielectric interposed between the gate contact layer and the channel and a first region that can include a silicide or a germanicide at a first end proximal to the source and a second region that can include the silicide or the germanicide at a second end proximal to the drain.