A semiconductor device, the device including: a first silicon layer including a first single crystal silicon; a first metal layer disposed over the first silicon layer; a second metal layer disposed over the first metal layer; a first level including a plurality of transistors, the first level disposed over the second metal layer, where the plurality of transistors include a second single crystal silicon; a third metal layer disposed over the first level; a fourth metal layer disposed over the third metal layer, where the fourth metal layer is aligned to the first metal layer with a less than 40 nm alignment error; and a via disposed through the first level, where the first level thickness is less than two microns.

A buried power rail is provided in a non-active device region. The buried power rail includes a dielectric liner located on a lower portion of a sidewall and a bottommost surface of the buried power rail. A dielectric cap is located on an upper portion of the sidewall of the buried power rail as well as on a topmost surface of the buried power rail. The dielectric cap is present during the fabrication of a functional gate structure and thus the problems associated with prior art buried power rails are circumvented. The dielectric cap can be removed after the functional gate structure has been formed and a via to buried power rail (VBPR) contact structure can be formed in contact with the buried power rail. In some applications, and after a gate cut process, a gate cut dielectric structure can be formed in contact with the dielectric cap.

A microelectronic device includes an integrated deep trench in a substrate, with a field oxide layer on the substrate. The integrated deep trench includes a of deep trench extending into semiconductor material of the substrate, a deep trench sidewall dielectric layer contacting the substrate and an electrically conductive trench-fill material contacting the deep trench sidewall dielectric layer. The conductive trench-fill material is covered during the formation of the field oxide layer to minimize the trench-fill seam void volume. Minimizing the trench-fill seam void volume minimizes optical defectivity observed in subsequent yield enhancement. The integrated deep trench may be configured as a capacitor or may be configured as a contact to the underlying substrate.

A microelectronic device includes an integrated deep trench in a substrate, with a field oxide layer on the substrate. The integrated deep trench includes a of deep trench extending into semiconductor material of the substrate, a deep trench sidewall dielectric layer contacting the substrate and an electrically conductive trench-fill material contacting the deep trench sidewall dielectric layer. The conductive trench-fill material is covered during the formation of the field oxide layer to minimize the trench-fill seam void volume. Minimizing the trench-fill seam void volume minimizes optical defectivity observed in subsequent yield enhancement. The integrated deep trench may be configured as a capacitor or may be configured as a contact to the underlying substrate.

A 3D semiconductor device, the device comprising: a first level comprising a first single crystal layer, said first level comprising first transistors, wherein each of said first transistors comprises a single crystal channel; first metal layers interconnecting at least said first transistors; a second metal layer overlaying said first metal layers; and a second level comprising a second single crystal layer, said second level comprising second transistors, wherein said second level overlays said first level, wherein at least one of said second transistors comprises a gate all around structure, wherein said second level is directly bonded to said first level, and wherein said bonded comprises direct oxide to oxide bonds.

A 3D semiconductor device including: a first level including a single crystal silicon layer and a plurality of first transistors each including a single crystal channel; a first metal layer overlaying the plurality of first transistors; a second metal layer overlaying the first metal layer; a third metal layer overlaying the second metal layer; a second level, where the second level overlays the first level and includes a plurality of second transistors; a fourth metal layer overlaying the second level; and a connective path between the fourth metal layer and either the third metal layer or the second metal layer, where the connective path includes a via disposed through the second level and has a diameter of less than 500 nm and greater than 5 nm, where the third metal layer is connected to provide a power or ground signal to at least one of the second transistors.

Structures with altered crystallinity beneath semiconductor devices and methods associated with forming such structures. Trench isolation regions surround an active device region composed of a single-crystal semiconductor material. A first non-single-crystal layer is arranged beneath the trench isolation regions and the active device region. A second non-single-crystal layer is arranged beneath the trench isolation regions and the active device region. The first non-single-crystal layer is arranged between the second non-single-crystal layer and the active device region.

A method of fabricating a metal mask includes receiving a conductive substrate with a first surface, a second surface opposite to the first surface, a third surface connecting the first and second surfaces, and a fourth surface opposite to the third surface and connecting the first and second surfaces. The method further includes forming trenches in a direction from the first surface to the second surface and protrusions in the conductive substrate. The trenches and the protrusions are alternately arranged. The method further includes filling the trenches with an insulation material covering a first area of the protrusions, forming a metal layer on the conductive substrate overlying a second area different from the first area of the protrusions, removing the insulation material, and removing the conductive substrate. The metal layer becomes a metal mask with a three-dimensional structure including strip-shaped structures.

A method of manufacturing a DRAM includes proving a substrate having active regions. First bit line structures are buried in the substrate. Each of first bit line structures extends along a first direction. Every two of the first bit line structures are disposed between two neighboring ones of the active regions arranged along a second direction. A plurality of pillar structures are formed arranged along the first direction by dividing each of the active regions. Second bit line structures are formed. Each of the second bit line structures is located between the pillar structures of a corresponding one of the active regions and extends through the corresponding one of the active regions along the second direction to be disposed on the first bit line structures at two sides of the corresponding one of the active regions and be electrically connected to the first bit line structures below.

Embodiments herein include semiconductor structures with a first source/drain (S/D) connected to a first field-effect transistor (FET) region, a second S/D connected to a second FET region, and a buried power rail (BPR) region. The BPR region may include a BPR, a first dielectric liner lining a first lateral side of the BPR region, and a second dielectric liner lining a second lateral side. The first dielectric liner isolates the BPR from the first FET region and the first S/D, and the second dielectric liner isolates the BPR from the second FET region. Embodiments may also include a contact electrically connecting the second S/D and the BPR through a second lateral side of the BPR region. The liners enable the BPR to be formed after the formation of gates and the S/Ds, so that the BPR does not cause problems during annealing processes of the gates and the S/Ds.