A 3D semiconductor device including: a first level including a plurality of first single-crystal transistors; a plurality of memory control circuits formed from at least a portion of the plurality of first single-crystal transistors; a first metal layer disposed atop the plurality of first single-crystal transistors; a second metal layer disposed atop the first metal layer; a second level disposed atop the second metal layer, the second level including a plurality of second transistors; a third level including a plurality of third transistors, where the third level is disposed above the second level; a third metal layer disposed above the third level; and a fourth metal layer disposed above the third metal layer, where the plurality of second transistors are aligned to the plurality of first single crystal transistors with less than 140 nm alignment error, the second level includes first memory cells, the third level includes second memory cells.

Aspects of the present disclosure provide a method for fabricating a semiconductor structure. For example, the method can include forming a stack of metal structures on a substrate, the stack of metal structures including multiple metal structures that are vertically stacked over and electrically separated from one another, each of the metal structures including a ring and one or more pad contacts extending from the ring, the rings of the metal structures being vertically aligned with one another. The method can also include forming one or more channel structures within the rings of the metal structures, the channel structures being electrically separated from one another and electrically separated from the substrate. The method can also include forming one or more interconnections that extend from a position above the stack of metal structures to corresponding one or more of the pad contacts of the metal structures.

A device structure is disclosed. The device structure includes a channel region having a first surface facing an underlying substrate and a second surface opposite to the first surface. The device structure includes a gate at least partially surrounding the channel region. The gate includes a gate dielectric and a gate conductor, in which the gate dielectric separates the gate conductor from the channel region. The device structure includes self-aligned source and drain regions (S/D regions) contacting the first and second surfaces, respectively.

A vertical FET includes a channel fin between a bottom source/drain (S/D) region and a top S/D region, a gate upon a sidewall of the channel fin, a top metallization upon the top S/D region, a first contact metallization connected to the gate, a second contact metallization connected to the bottom S/D region, a first vertical liner between a portion of the gate and the first contact metallization, and a second vertical liner between the top metallization and the second contact metallization. The vertical FET may be fabricated by forming a self-aligned block and utilizing the self-aligned block to e.g., prevent gate to gate shorting during replacement gate formation or processing.

Structures and methods are disclosed in which a layer stack can be formed with a plurality of layers of a metal, where each of the layers of metal can be separated by a layer of a dielectric. An opening in the layer stack can be formed such that a semiconductor layer beneath the plurality of layers of the metal is uncovered. One or more vertical channel structures can be formed within the opening by epitaxial growth. The vertical channel structure can include a vertically oriented transistor. The vertical channel structure can include an interface of a silicide metal with a first metal layer of the plurality of metal layers. The interface can correspond to one of a source or a drain connection of a transistor. The silicide metal can be annealed above a temperature threshold to form a silicide interface between the vertical channel structure and the first metal layer.

Provided on a substrate 1 are an N.sup.+ layer connecting to a source line SL, a first Si pillar as a P.sup.+ layer standing in an upright position along the vertical direction, and a second Si pillar as a P layer. An N.sup.+ layer connecting to a bit line BL is provided on the second Si pillar. A first gate insulating layer is provided so as to surround the first Si pillar, and a second gate insulating layer is provided so as to surround the second Si pillar. A first gate conductor layer connecting to a plate line PL is provided so as to surround the first insulating layer, and a second gate conductor layer connecting to a word line WL is provided so as to surround the second insulating layer. A voltage applied to each of the source line SL, the plate line PL, the word line WL, and the bit line BL is controlled to perform a data write operation for retaining holes, which have been generated through an impact ionization phenomenon or using a gate induced drain leakage current, in a channel region, and a data erase operation for removing the holes from the channel region.

A memory device includes pages arranged in columns and each constituted by a plurality of memory cells on a substrate, voltages applied to a first gate conductor layer, a second gate conductor layer, a first impurity layer, and a second impurity layer in each memory cell included in each of the pages are controlled to perform a page write operation of retaining, inside a channel semiconductor layer, a group of positive holes generated by an impact ionization phenomenon or by a gate-induced drain leakage current, and the voltages applied to the first gate conductor layer, the second gate conductor layer, the first impurity layer, and the second impurity layer are controlled to perform a page erase operation of discharging the group of positive holes from inside the channel semiconductor layer. The first impurity layer of the memory cell is connected to a source line, the second impurity layer thereof is connected to a bit line, one of the first gate conductor layer or the second gate conductor layer thereof is connected to a word line, the other of the first gate conductor layer or the second gate conductor layer thereof is connected to a first driving control line, and the bit lines are connected to sense amplifier circuits with a switch circuit therebetween. In a page read operation, page data in a group of memory cells selected by the word line is read to the sense amplifier circuits, and in a page addition read operation, at least two sets of page data selected by at least two word lines in multiple selection are added up for each of the bit lines and read to a corresponding one of the sense amplifier circuits.

An N.sup.+ layer, a Si base material formed of a first channel region and a second channel region, and an N.sup.+ layer are disposed parallel to a substrate so as to be connected to each other. A first gate insulating layer that surrounds the first channel region and a second gate insulating layer that surrounds the second channel region are disposed. A first gate conductor layer that surrounds the first gate insulating layer and a second gate conductor layer that surrounds the second gate insulating layer are disposed. The first gate conductor layer is connected to a plate line PL, and the second gate conductor layer is connected to a word line WL. The N.sup.+ layer is connected to a source line, and the N.sup.+ layer is connected to a bit line BL. These constitute one dynamic flash memory cell. A plurality of cells are disposed in the vertical direction and in the horizontal direction relative to the substrate to form a dynamic flash memory.

On a substrate, an N.sup.+ layer connecting to a source line SL, a first Si pillar standing in a perpendicular direction, and a second Si pillar on the first Si pillar are disposed. In a central portion of the first Si pillar, a P.sup.+ layer is disposed, and a P layer is disposed so as to surround the P.sup.+ layer. In a central portion of the second Si pillar, a P.sup.+ layer is disposed, and a P layer is disposed so as to surround the P.sup.+ layer. On the second Si pillar, an N.sup.+ layer is disposed so as to connect to a bit line BL. A first gate insulating layer is disposed so as to surround the first Si pillar, and a second gate insulating layer is disposed so as to surround the second Si pillar. A first gate conductor layer is disposed so as to surround the first insulating layer and to connect to a plate line PL, and a second gate conductor layer is disposed so as to surround the second insulating layer and to connect to a word line WL. Voltages applied to the source line SL, the plate line PL, the word line WL, and the bit line BL are controlled, to perform a data retention operation of retaining a hole group generated within a channel region due to an impact ionization phenomenon or a gate induced drain leakage current and a data erase operation of discharging the hole group from within the channel region.

Embodiments of the present invention are directed to fabrication method and resulting structures for vertical tunneling field effect transistors (VFETs) having an oxygen vacancy passivating bottom spacer. In a non-limiting embodiment of the invention, a first semiconductor fin is formed in a first region of a substrate and a second semiconductor fin is formed in a second region of the substrate. A bilayer bottom spacer is formed in direct contact with sidewalls of the semiconductor fins. The bilayer bottom spacer includes a first layer and an oxygen-donating second layer positioned on the first layer. A first dielectric film is formed on the sidewalls of the first semiconductor fin. The first dielectric film terminates on the first layer. A second dielectric film is formed on the sidewalls of the second semiconductor fin. The second dielectric film extends onto a surface of the oxygen-donating second layer.