A semiconductor device has a semiconductor material in a substrate. The semiconductor device has an MOS transistor. A trench in the substrate extends from a top surface of the substrate) into the semiconductor material. A shield is disposed in the trench. The shield has a contact portion which extends toward a top surface of the trench. A gate of the MOS transistor is disposed in the trench over the shield. The gate is electrically isolated from the shield. The gate is electrically isolated from the contact portion of the shield by a shield isolation layer which covers an angled surface of the contact portion extending toward the top of the trench. Methods of forming the semiconductor device are disclosed.

The present disclosure describes a fabrication method that prevents divots during the formation of isolation regions in integrated circuit fabrication. In some embodiments, the method of forming the isolation regions includes depositing a protective layer over a semiconductor layer; patterning the protective layer to expose areas of the semiconductor layer; depositing an oxide on the exposed areas the semiconductor layer and between portions of the patterned protective layer; etching a portion of the patterned protective layer to expose the semiconductor layer; etching the exposed semiconductor layer to form isolation openings in the semiconductor layer; and filling the isolation openings with a dielectric to form the isolation regions.

A method of forming an oxide structure is disclosed. The method includes forming trenches on a top surface of a substrate and performing a surface treatment process on the substrate. The surface treatment includes forming an amorphous layer on the substrate, removing a portion of the amorphous layer to form a liner layer, and forming a dielectric liner on the liner layer. The liner layer formed are substantially uniform in thickness to prevent contamination and pinhole defects on the oxide structure.

Provided is a method for manufacturing a semiconductor device including: patterning a substrate to form a plurality of active patterns including two adjacent active patterns having a first trench therebetween; forming a semiconductor layer on the plurality of active patterns to cover the plurality of active patterns; forming a device isolation layer on the semiconductor layer to cover the semiconductor layer for oxidization and fill the first trench; patterning the device isolation layer and the plurality of active patterns so that a second trench intersecting the first trench is formed and the two active patterns protrudes from the device isolation layer in the second trench; and forming a gate electrode in the second trench. Here, a first thickness of the semiconductor layer covering a top surface of each of the two active patterns is greater than a second thickness of the semiconductor layer covering a bottom of the first trench.

A method of forming an oxide structure is disclosed. The method includes forming trenches on a top surface of a substrate and performing a surface treatment process on the substrate. The surface treatment includes forming an amorphous layer on the substrate, removing a portion of the amorphous layer to form a liner layer, and forming a dielectric liner on the liner layer. The liner layer formed are substantially uniform in thickness to prevent contamination and pinhole defects on the oxide structure.

A semiconductor structure is provided. The semiconductor structure includes a substrate, a first trench, and a second trench. The substrate has a first region and a second region. The first trench is formed in the substrate within the first region. The first trench is surrounded by a first protrusion structure having a top portion and sidewalls. The second trench is formed in the substrate within the second region. The second trench is surrounded by a second protrusion structure having a top portion and sidewalls. The second trench is deeper than the first trench. The connection portion between the top portion and the sidewalls of the second protrusion structure has a greater radius of curvature than the connection portion between the top portion and the sidewalls of the first protrusion structure.

The present disclosure describes a fabrication method that prevents divots during the formation of isolation regions in integrated circuit fabrication. In some embodiments, the method of forming the isolation regions includes depositing a protective layer over a semiconductor layer; patterning the protective layer to expose areas of the semiconductor layer; depositing an oxide on the exposed areas the semiconductor layer and between portions of the patterned protective layer; etching a portion of the patterned protective layer to expose the semiconductor layer; etching the exposed semiconductor layer to form isolation openings in the semiconductor layer; and filling the isolation openings with a dielectric to form the isolation regions.

The present disclosure describes a fabrication method that prevents divots during the formation of isolation regions in integrated circuit fabrication. In some embodiments, the method of forming the isolation regions includes depositing a protective layer over a semiconductor layer; patterning the protective layer to expose areas of the semiconductor layer; depositing an oxide on the exposed areas the semiconductor layer and between portions of the patterned protective layer; etching a portion of the patterned protective layer to expose the semiconductor layer; etching the exposed semiconductor layer to form isolation openings in the semiconductor layer; and filling the isolation openings with a dielectric to form the isolation regions.

Disclosed is a method for manufacturing an isolation structure for LDMOS, the method comprising: forming a first groove on the surface of a wafer; filling the first groove with silicon oxide; removing part of the surface of the silicon oxide within the first groove by means of etching; forming a silicon oxide corner structure at the corner of the top of the first groove by means of thermal oxidation; depositing a nitrogen-containing compound on the surface of the wafer to cover the surface of the silicon oxide within the first groove and the surface of the silicon oxide corner structure; dry-etching the nitrogen-containing compound to remove the nitrogen-containing compound from the surface of the silicon oxide within the first groove, and thereby forming a nitrogen-containing compound side wall residue; with the nitrogen-containing compound side wall residue as a mask, continuing to etch downwards to form a second groove; forming a silicon oxide layer on the side wall and the bottom of the second groove; removing the nitrogen-containing compound side wall residue; and filling the first groove and the second groove with silicon oxide.

A stacked field effect transistor (FET) device. The device includes an opening in a shallow trench isolation (STI) region on a substrate. The device also includes an epitaxy region located on the substrate at a bottom portion of STI region in the opening. The device further includes a substrate contact that directly contacts the epitaxy region.