A shielded gate trench MOSFET device structure is provided. The device structure includes MOS gate trenches and p body contact trenches formed in an n type epitaxial silicon layer overlying an n+ silicon substrate. Each MOS gate trench includes a gate trench stack having a lower n+ shield poly silicon layer separated from an upper n+ gate poly silicon layer by an inter poly dielectric layer. The upper and lower poly silicon layers are also laterally isolated at the areas where the lower poly silicon layer extends to silicon surface by selectively removing portion of the upper poly silicon and filling the gap with a dielectric material. The method is used to form both MOS gate trenches and p body contact trenches in self-aligned or non self-aligned shielded gate trench MOSFET device manufacturing.

One embodiment provides a semiconductor device. The device comprises a substrate having a first face and a second face, a well region, a source region disposed in the well region, a contact region contacting the well region and the source region, a Schottky region, and a source metal layer. A first part of the source metal layer contacts the Schottky region to form a Schottky diode. The Schottky region is surrounded by the contact region and the well region in a first plane perpendicular to a direction from the first face toward the second face.

One embodiment provides a semiconductor device. The device comprises a substrate having a first face and a second face, a well region, a source region disposed in the well region, a contact region contacting the well region and the source region, a Schottky region, and a source metal layer. A first part of the source metal layer contacts the Schottky region to form a Schottky diode. The Schottky region is surrounded by the contact region and the well region in a first plane perpendicular to a direction from the first face toward the second face.

A method of forming a gate of a planar metal oxide semiconductor field effect transistor (MOSFET) reduces gate-drain capacitance. The method may include forming a first gate dielectric portion of the planar MOSFET with a first thickness that is configured to reduce the gate-drain capacitance of the planar MOSFET, forming a second gate dielectric portion of the planar MOSFET on the substrate with a second thickness less than the first thickness, and forming the gate of the planar MOSFET on the first gate dielectric portion and the second gate dielectric portion on the substrate.

A method of forming a gate of a planar metal oxide semiconductor field effect transistor (MOSFET) reduces gate-drain capacitance. The method may include forming a first gate dielectric portion of the planar MOSFET with a first thickness that is configured to reduce the gate-drain capacitance of the planar MOSFET, forming a second gate dielectric portion of the planar MOSFET on the substrate with a second thickness less than the first thickness, and forming the gate of the planar MOSFET on the first gate dielectric portion and the second gate dielectric portion on the substrate.

A semiconductor device comprises a substrate comprising a cell region; a cell region isolation film in the substrate and extending along an outer edge of the cell region; a bit-line structure on the substrate and in the cell region, wherein the bit-line structure has a distal end positioned on the cell region isolation film; a cell spacer on a vertical side surface of the distal end of the bit-line structure; an etching stopper film extending along a side surface of the cell spacer and a top face of the cell region isolation film; and an interlayer insulating film on the etching stopper film, and on the side surface of the cell spacer, wherein the interlayer insulating film includes silicon nitride.

A shielded gate trench MOSFET device structure is provided. The device structure includes MOS gate trenches and p body contact trenches formed in an n type epitaxial silicon layer overlying an n+ silicon substrate. Each MOS gate trench includes a gate trench stack having a lower n+ shield poly silicon layer separated from an upper n+ gate poly silicon layer by an inter poly dielectric layer. The upper and lower poly silicon layers are also laterally isolated at the areas where the lower poly silicon layer extends to silicon surface by selectively removing portion of the upper poly silicon and filling the gap with a dielectric material. The method is used to form both MOS gate trenches and p body contact trenches in self-aligned or non self-aligned shielded gate trench MOSFET device manufacturing.

A shielded gate trench MOSFET device structure is provided. The device structure includes MOS gate trenches and p body contact trenches formed in an n type epitaxial silicon layer overlying an n+ silicon substrate. Each MOS gate trench includes a gate trench stack having a lower n+ shield poly silicon layer separated from an upper n+ gate poly silicon layer by an inter poly dielectric layer. The upper and lower poly silicon layers are also laterally isolated at the areas where the lower poly silicon layer extends to silicon surface by selectively removing portion of the upper poly silicon and filling the gap with a dielectric material. The method is used to form both MOS gate trenches and p body contact trenches in self-aligned or non self-aligned shielded gate trench MOSFET device manufacturing.

A power semiconductor device and a method of fabricating such a power semiconductor device are disclosed. In the method, spacers are formed, which cover sidewalls of a source polysilicon layer and reside on trench portions around the source polysilicon layer. As such, a contact is allowed to be directly formed above the source polysilicon layer, eliminating the need for a special photomask for defining a connection between the contact and the gate electrode, reducing the number of required steps, lowering the process cost and avoiding the risk of contact of the subsequently-formed contact above the source polysilicon layer with a gate polysilicon layer. With the spacers protecting a second oxide layer, during the subsequent formation of a source electrode, the implantation of some n-type ions into the second oxide layer, which may degrade the properties of the second oxide layer, is prevented.

A semiconductor device includes a first active region defined on a substrate, a first gate electrode across the first active region, a first drain region in the first active region at a position adjacent to the first gate electrode, an undercut region between the first active region and the first gate electrode, and a first gate spacer on a side surface of the first gate electrode and extending into the undercut region.