A method for fabricating a semiconductor device is provided. The method includes providing a substrate, having a cell region and a logic region and including a first conductive layer as a top layer, wherein shallow trench isolation (STI) structures are disposed in the substrate at cell region and the logic region. A first dry etching process is performed to preliminarily etch the first conductive layer and the STI structures at the cell region. A wet etching process is performed over the substrate to etch the STI structures down to a preserved height. A control gate stack is formed on the first conductive layer at the cell region. A second dry etching process is performed on a portion of the first conductive layer to form a floating gate under the control gate stack at the cell region and remove the first conductive layer at the logic region.

A method of forming a device with a silicon substrate having upwardly extending first and second fins. A first implantation forms a first source region in the first silicon fin. A second implantation forms a first drain region in the first silicon fin, and second source and drain regions in the second silicon fin. A first channel region extends between the first source and drain regions. A second channel region extends between the second source and drain regions. A first polysilicon deposition is used to form a floating gate that wraps around a first portion of the first channel region. A second polysilicon deposition is used to form an erase gate wrapping around first source region, a word line gate wrapping around a second portion of the first channel region, and a dummy gate wrapping around the second channel region. The dummy gate is replaced with a metal gate.

A method of forming a device with a silicon substrate having upwardly extending first and second fins. A first implantation forms a first source region in the first silicon fin. A second implantation forms a first drain region in the first silicon fin, and second source and drain regions in the second silicon fin. A first channel region extends between the first source and drain regions. A second channel region extends between the second source and drain regions. A first polysilicon deposition is used to form a floating gate that wraps around a first portion of the first channel region. A second polysilicon deposition is used to form an erase gate wrapping around first source region, a word line gate wrapping around a second portion of the first channel region, and a dummy gate wrapping around the second channel region. The dummy gate is replaced with a metal gate.

The present disclosure relates to a flash memory cell that includes a substrate and a floating gate structure over the substrate. The floating gate structure includes a first portion having a first top surface and a first thickness. The floating gate structure also includes a second portion having a second top surface and a second thickness that is different from the first thickness. The floating gate structure further includes a sidewall surface connecting the first and second top surfaces, and an angle between the first top surface and the sidewall surface of the floating gate structure is an obtuse angle. The flash memory cell also includes a control gate structure over the first and second portions of the floating gate structure.

Various embodiments of the present application are directed to an embedded memory boundary structure with a boundary sidewall spacer, and associated forming methods. In some embodiments, an isolation structure is disposed in a semiconductor substrate to separate a memory region from a logic region. A memory cell structure is disposed on the memory region and a cell boundary structure is formed on the isolation structure including a boundary sidewall spacer. A protecting dielectric layer is disposed on a top surface of the boundary sidewall spacer. The boundary sidewall spacer and the protecting dielectric layer provide a smooth boundary sidewall that is not subject to damage during formation of the logic device structure and, hence, is not subject to trapping high κ etch residue during formation of the logic device structure with HKMG technology.

A method of forming a memory device includes forming a floating gate on a memory cell area of a semiconductor substrate, having an upper surface terminating in an edge. An oxide layer is formed having first and second portions extending along the logic and memory cell regions of the substrate surface, respectively, and a third portion extending along the floating gate edge. A non-conformal layer is formed having a first, second and third portions covering the oxide layer first, second and third portions, respectively. An etch removes the non-conformal layer third portion, and thins but does not entirely remove the non-conformal layer first and second portions. An etch reduces the thickness of the oxide layer third portion. After removing the non-conformal layer first and second portions, a control gate is formed on the oxide layer second portion and a logic gate is formed on the oxide layer first portion.

An integrated circuit device includes a semiconductor substrate having a memory area and a logic area. A memory cell in the memory area includes a select gate separated from a floating gate by a floating gate spacer. A select gate spacer is formed on a side of the select gate opposite the floating gate. The select gate spacer has a uniform thickness over most of the select gate. The first layer of the select gate spacer may be formed by oxidizing the select gate electrode. A second layer of the select gate spacer may be formed by atomic layer deposition. the memory area may be covered by a protective layer while spacers are formed adjacent logic gates in the logic region.

A semiconductor device includes a peripheral circuit region comprising a first substrate, circuit elements on the first substrate, a first insulating layer covering the circuit elements, and a contact plug passing through the first insulating layer and disposed to be connected to the first substrate; and a memory cell region comprising a second substrate, gate electrodes on the second substrate and stacked in a vertical direction, and channel structures passing through the gate electrodes, wherein the contact plug comprises a metal silicide layer disposed to contact the first substrate and having a first thickness, a first metal nitride layer on the metal silicide layer to contact the metal silicide layer and having a second thickness, greater than the first thickness, a second metal nitride layer on the first metal nitride layer, and a conductive layer on the second metal nitride layer.

A second gate dielectric film material and a memory gate electrode material are formed on a semiconductor substrate. The memory gate electrode material and the second gate dielectric film material formed in a peripheral circuit forming region are removed, and a part of each of the memory gate electrode material and the second gate dielectric film material is left in the memory cell forming region. Thereafter, in a state that the semiconductor substrate in the memory cell forming region is covered with a part of each of the memory gate electrode material and the second gate dielectric film material, heat treatment is performed to the semiconductor substrate to form a third gate dielectric film on the semiconductor substrate located in the peripheral circuit forming region. Thereafter, a memory gate electrode and a second gate dielectric film are formed.

A photo mask includes a plurality of device features, a first assist feature, and a second assist feature. The device features are in a patterning region of a device region. The first assist feature are in the patterning region and adjacent to the device features. The first assist feature is for correcting an optical proximity effect in a photolithography process. The second assist feature is in a non-patterning region of the device region. The second assist feature is a sub-resolution correction feature, and a first distance between the second assist feature and one of the device features closest to the second assist feature is greater than a second distance between adjacent two of the device features.