A semiconductor device includes a semiconductor film and a gate structure on the semiconductor film. The gate structure includes a multi-stepped gate dielectric on the semiconductor film and a gate electrode on the multi-stepped gate dielectric. The multi-stepped gate dielectric includes a first gate dielectric segment having a first thickness and a second gate dielectric segment having a second thickness that is less than the first thickness.

A semiconductor device includes a semiconductor layer, a drift region, a source area, a well region, a drain area, and a dielectric film. The drift region and the source area are formed in the semiconductor layer. The well region is formed in the semiconductor layer and between the drift region and the source area. The drain area is formed in the drift region. The dielectric film is formed in the drift region and is located between the source area and the drain area. The dielectric film includes a proximate end portion and a distal end portion which are proximate to and distal from the source area, respectively, and which are asymmetrical to each other.

A power device includes: a semiconductor layer, a well region, a body region, a gate, a source, a drain, a first salicide block (SAB) layer and a second SAB layer. The first SAB layer is formed on a top surface of the semiconductor layer, and is located between the gate and the drain, wherein a part of the well is located vertically below and in contact with the first SAB layer. The second SAB layer is formed vertically above and in contact with the first SAB layer.

A power device includes: a semiconductor layer, a well region, a body region, a gate, a source, a drain, a field oxide region, and a self-aligned drift region. The field oxide region is formed on an upper surface of the semiconductor layer, wherein the field oxide region is located between the gate and the drain. The field oxide region is formed by steps including a chemical mechanical polish (CMP) process step. The self-aligned drift region is formed in the semiconductor layer, wherein the self-aligned drift region is entirely located vertically below and in contact with the field oxide region.

A semiconductor device includes a deep well region located on a substrate, a drift region located in the deep well region, a first gate electrode that overlaps with the first body region and the drift region, a second gate electrode that overlaps with the second body region and the drift region, a first source region and a second source region located in the first and second body regions, respectively, a drain region located in the drift region and disposed between the first gate electrode and the second gate electrode, a silicide layer located on the substrate, a first non-silicide layer located between the drain region and the first gate electrode, wherein the first non-silicide layer extends over a top surface of the first gate electrode, and a first field plate contact plug in contact with the first non-silicide layer.

A high voltage transistor structure including a substrate, a first drift region, a second drift region, a first cap layer, a second cap layer, a gate structure, a first source and drain region, and a second source and drain region is provided. The first and second drift regions are disposed in the substrate. The first and second cap layers are respectively disposed on the first and second drift regions. The gate structure is disposed on the substrate and located over at least a portion of the first drift region and at least a portion of the second drift region. The first and second source and drain regions are respectively disposed in the first and second drift regions and located on two sides of the gate structure. The size of the first drift region and the size of the second drift region are asymmetric.

Various embodiments of the present application are directed towards a method to integrate NVM devices with a logic or BCD device. In some embodiments, an isolation structure is formed in a semiconductor substrate. The isolation structure demarcates a memory region of the semiconductor substrate, and further demarcates a peripheral region of the semiconductor substrate. The peripheral region may, for example, correspond to BCD device or a logic device. A doped well is formed in the peripheral region. A dielectric seal layer is formed covering the memory and peripheral regions, and further covering the doped well. The dielectric seal layer is removed from the memory region, but not the peripheral region. A memory cell structure is formed on the memory region using a thermal oxidation process. The dielectric seal layer is removed from the peripheral region, and a peripheral device structure including a gate electrode is formed on the peripheral region.

A semiconductor device and a forming method thereof, the semiconductor device includes a first and a second wells, a source region, a drain region, two gate structures and at least one doping region. The first well with a first conductive type is disposed in a substrate, and the source region is disposed in the first well. The second well with a second conductive type is disposed adjacent to the first well in a substrate, and the drain region is disposed in the second well. Two gate structures are disposed on the substrate between the source region and the drain region. At least one doping region with the first conductive type is disposed in the second well between the two gate structures.

A structure includes a laterally diffused (LD) MOSFET with an n-type drift region disposed on a surface of a substrate and a p-type body region contained in the drift region. The structure further includes an n-type source region contained in the p-type body region; an n-type drain region contained in the n-type drift region; a gate electrode disposed on a gate dielectric overlying a portion of the p-type body region and the n-type drift region and an electrically conductive field shield member disposed within the n-type drift region at least partially beneath the p-type body region and generally parallel to the gate electrode. The electrically conductive buried field shield member is contained within and surrounded by a layer of buried field shield oxide and is common to both a first LD MOSFET and a second LD MOSFET that are connected in parallel. Methods to fabricate the structure are also disclosed.

A semiconductor device includes a P-type body region and an N-type drift region disposed in a substrate; a gate electrode, disposed on the P-type body region and the N-type drift region, including a high concentration doping region and a high resistance region, wherein a dopant concentration of the high concentration doping region is higher than a dopant concentration of the high resistance region; a spacer disposed on a side of the gate electrode; a highly doped source region disposed in the P-type body region; and a highly doped drain region disposed in the N-type body region. The high concentration doping region overlaps the P-type body region, and the high resistance region overlaps the N-type drift region.