According to one embodiment, a semiconductor device includes a memory cell array including a first memory cell provided on a substrate and a second memory cell provided on the substrate. The memory cell array includes a charge storage layer provided on the substrate and a control electrode provided on the charge storage layer. A coupling ratio of the second memory cell is different from a coupling ratio of the first memory cell.

The present description concerns a ROM including at least one first rewritable memory cell. In an embodiment, a method of manufacturing a read-only memory (ROM) comprising a plurality of memory cells is proposed. Each of the plurality of memory cells includes a rewritable first transistor and a rewritable second transistor. An insulated gate of the rewritable first transistor is connected to an insulated gate of the rewritable second transistor. The method includes successively depositing, on a semiconductor structure, a first insulating layer and a first gate layer, wherein the first insulating layer is arranged between the semiconductor structure and the first gate layer, wherein the rewritable second transistor further includes a well-formed between an associated first insulating layer and the semiconductor structure, and wherein the rewritable first insulating layer is in direct contact with the semiconductor structure; and successively depositing a second insulating layer and a second gate layer.

A semiconductor device includes first nanostructures vertically separated from one another, a first gate structure wrapping around each of the first nanostructures, and second nanostructures vertically separated from one another. The semiconductor device also includes a second gate structure wrapping around the second nanostructures, a first drain/source structure coupled to a first end of the first nanostructures, a second drain/source structure coupled to both of a second end of the first nanostructures and a first end of the second nanostructures, and a third drain/source structure coupled to a second end of the second nanostructures. The first drain/source structure has a first doping type, the second and third drain/source structures have a second doping type, and the first doping type is opposite to the second doping type.

An occupied area of the switch circuit electrically connected to a memory cell is reduced to reduce the size of a semiconductor device. A semiconductor device according to an embodiment includes a memory cell on a semiconductor substrate and a semiconductor chip in which a switch circuit electrically connected to the memory cell is formed, wherein the switch circuit includes a second transistor electrically connected to the memory cell, and the second transistor includes a second word gate formed on the semiconductor substrate through a third gate insulating film, and a second coupling gate formed on the semiconductor substrate through a fourth gate insulating film having a thickness greater than that of the third gate insulating film, wherein a voltage higher than a voltage applied to the second word gate is applied to the second coupling gate of the second transistor when a current is applied to the memory cell.

The present invention discloses a mixed three-dimensional memory (3D-M.sub.x). It comprises memory arrays (or, memory blocks) of different sizes. In a 3D-M.sub.x with mixed memory blocks, the memory blocks with different sizes are formed side-by-side. In a 3D-M.sub.x with mixed memory arrays, a plurality of small memory arrays are formed side-by-side underneath a single large memory array.

A one-time programmable (OTP) vertical field-effect transistor (VFET) can be fabricated on the top surface of an integrated circuit (IC) substrate having a fin. A doped layer can be deposited onto the top surface to create an OTP VFET drain. A dielectric layer can be formed onto side surfaces of the fin, and a gate dielectric layer formed onto side surfaces of the dielectric layer. A metal layer formed onto side surfaces of the gate dielectric layer can create an OTP VFET gate. An electrically insulative top spacer layer can then be attached to top edges of the dielectric, the gate dielectric layer, and the metal layer. A doped structure formed onto the top surface of the fin can create an OTP VFET source. A voltage applied to a portion of the gate dielectric layer can cause dielectric breakdown, which can be used to store a data value.

The present description concerns a ROM including at least one first rewritable memory cell. In an embodiment, a method of manufacturing a read-only memory (ROM) comprising a plurality of memory cells is proposed. Each of the plurality of memory cells includes a rewritable first transistor and a rewritable second transistor. An insulated gate of the rewritable first transistor is connected to an insulated gate of the rewritable second transistor. The method includes successively depositing, on a semiconductor structure, a first insulating layer and a first gate layer, wherein the first insulating layer is arranged between the semiconductor structure and the first gate layer, wherein the rewritable second transistor further includes a well-formed between an associated first insulating layer and the semiconductor structure, and wherein the rewritable first insulating layer is in direct contact with the semiconductor structure; and successively depositing a second insulating layer and a second gate layer.

A read-only memory (ROM) structure is provided. The ROM device structure includes a first gate structure formed over a substrate, and the first gate structure includes a first work function layer with a first thickness. The ROM device structure includes an isolation structure formed over the substrate, and the isolation structure is adjacent to the first gate structure. The isolation structure includes a second work function layer with a second thickness, and the second thickness is larger than or smaller than the first thickness. The ROM device structure also includes a first contact structure formed over the substrate, and the first contact structure is between the first gate structure and the isolation structure.

A read-only memory (ROM) structure is provided. The ROM device structure includes an active region formed over a substrate and a first group of word lines formed over the active region. The first group of word lines includes at least two word lines. The ROM device structure includes a second group of word lines formed on the active region, and the second group of word lines includes at least two word lines. The ROM device structure further includes an isolation line between the first group of word lines and the second group of word lines and over the active region. The first group of word lines, the second group of word lines, and the isolation line are formed in a second metal layer.

A vertically integrated circuit device can include a substrate having a first region reserved for first functional circuits of the vertically integrated circuit device, where the first functional circuits has a substantially constant top surface level across the first region and having a second region reserved for second functional circuits of the vertically integrated circuit device and spaced apart from the first region. The second functional circuits can have a varied top surface level across the second region. A doped oxidation suppressing material can be included in the substrate and can extend from the first region to the second region at an interface of the substrate with the first functional circuits and the second functional circuits, respectively.