A method for manufacturing a polysilicon SOI substrate including a cavity. The method includes: providing a silicon substrate including a sacrificial layer thereon; producing a first polysilicon layer on the sacrificial layer; depositing a structuring layer on the first polysilicon layer; introducing trenches through the structuring layer, the first polysilicon layer, and the sacrificial layer up to the silicon substrate; producing a cavity in the silicon substrate by etching, an etching medium being conducted thereto through the trenches; producing a second polysilicon layer on the first polysilicon layer, the trenches being thereby closed. A micromechanical device is also described.

An integrated circuit may be formed by forming a buried isolation layer in an isolation recess in a single-crystal silicon-based substrate. Exposed lateral surfaces of the substrate at the buried isolation layer are covered with a dielectric sidewall. A seed trench is formed through the buried isolation layer to expose the substrate. A single-crystal silicon-based seed layer is formed through the seed trench, extending above the top surface of the buried isolation layer. A silicon-based non-crystalline layer is formed contacting the seed layer. A cap layer is formed over the non-crystalline layer. A radiant-induced recrystallization process converts the non-crystalline layer to a single-crystal layer aligned with the seed layer. The cap layer is removed and the single-crystal layer is planarized, leaving an isolated semiconductor layer over the buried isolation layer.

The present invention provides a semiconductor device, including a substrate, a first semiconductor layer, a plurality of first sub recess, a plurality of insulation structures and a first top semiconductor layer. The substrate has a first region disposed within an STI. The first semiconductor layer is disposed in the first region. The first sub recesses are disposed in the first semiconductor layer. The insulation structures are disposed on the first semiconductor layer. The first top semiconductor layer forms a plurality of fin structures, which are embedded in the first sub recesses, arranged alternatively with the insulation structures and protruding over the insulation structures.

An integrated circuit may be formed by forming a buried isolation layer in an isolation recess in a single-crystal silicon-based substrate. Exposed lateral surfaces of the substrate at the buried isolation layer are covered with a dielectric sidewall. A seed trench is formed through the buried isolation layer to expose the substrate. A single-crystal silicon-based seed layer is formed through the seed trench, extending above the top surface of the buried isolation layer. A silicon-based non-crystalline layer is formed contacting the seed layer. A cap layer is formed over the non-crystalline layer. A radiant-induced recrystallization process converts the non-crystalline layer to a single-crystal layer aligned with the seed layer. The cap layer is removed and the single-crystal layer is planarized, leaving an isolated semiconductor layer over the buried isolation layer.

A method for making a semiconductor device may include forming buried spaced-apart insulator regions in a semiconductor substrate, and forming a monocrystalline semiconductor layer on the semiconductor substrate defining respective localized semiconductor on insulator (SOI) regions above the buried insulator regions, and respective localized bulk semiconductor regions laterally between adjacent SOI regions. The method may also include forming a superlattice in the monocrystalline semiconductor layer. The superlattice may include stacked groups of layers, with each group of layers including stacked base semiconductor monolayers defining a base semiconductor portion, and at least one non-semiconductor monolayer constrained within a crystal lattice of adjacent base semiconductor portions. The method may further include forming semiconductor devices in the monocrystalline layer, with some of the semiconductor devices in the localized SOI regions, and some other semiconductor devices in the localized bulk semiconductor regions.

A semiconductor device may include a semiconductor substrate, buried spaced-apart insulator regions in the substrate, and a monocrystalline semiconductor layer on the semiconductor substrate defining respective localized semiconductor on insulator (SOI) regions above the buried insulator regions, and respective localized bulk semiconductor regions laterally between adjacent SOI regions. The semiconductor device may also include a superlattice in the monocrystalline semiconductor layer. The superlattice may include stacked groups of layers, with each group of layers including stacked base semiconductor monolayers defining a base semiconductor portion, and at least one non-semiconductor monolayer constrained within a crystal lattice of adjacent base semiconductor portions. The semiconductor device may further include semiconductor devices in the monocrystalline layer, with at least some of the semiconductor devices in the localized SOI regions, and at least some other semiconductor devices in the localized bulk semiconductor regions.

An integrated circuit may be formed by forming an isolation recess in a single-crystal silicon-based substrate. Sidewall insulators are formed on sidewalls of the isolation recess. Thermal oxide is formed at a bottom surface of the isolation recess to provide a buried isolation layer, which does not extend up the sidewall insulators. A single-crystal silicon-based semiconductor layer is formed over the buried isolation layer and planarized to be substantially coplanar with the substrate adjacent to the isolation recess, thus forming an isolated semiconductor layer over the buried isolation layer. The isolated semiconductor layer is laterally separated from the substrate.

An integrated circuit may be formed by forming an isolation recess in a single-crystal silicon-based substrate. Sidewall insulators are formed on sidewalls of the isolation recess. Thermal oxide is formed at a bottom surface of the isolation recess to provide a buried isolation layer, which does not extend up the sidewall insulators. A single-crystal silicon-based semiconductor layer is formed over the buried isolation layer and planarized to be substantially coplanar with the substrate adjacent to the isolation recess, thus forming an isolated semiconductor layer over the buried isolation layer. The isolated semiconductor layer is laterally separated from the substrate.

The present invention provides a semiconductor device, including a substrate, a first semiconductor layer, a plurality of first sub recess, a plurality of insulation structures and a first top semiconductor layer. The substrate has a first region disposed within an STI. The first semiconductor layer is disposed in the first region. The first sub recesses are disposed in the first semiconductor layer. The insulation structures are disposed on the first semiconductor layer. The first top semiconductor layer forms a plurality of fin structures, which are embedded in the first sub recesses, arranged alternatively with the insulation structures and protruding over the insulation structures.