An IGBT device includes a drift region of a first doping type; a plurality of pillar regions of the second doping type, disposed at intervals in the lateral direction within the drift region; and a transition layer of the first doping type, connected under the pillar region. The thickness of the transition layer is larger than 2 microns and less than or equal to 11 microns, and the doping concentration of the transition layer ranges from larger than or equal to 2.410.sup.14/cm.sup.3 to less than or equal to 2.410.sup.16/cm.sup.3, in order to solve the technical problem of a large turn-off energy loss due to the tail current of the conventional SJ-IGBT device in the turn-off stage.

Methods and structures for forming strained-channel finFETs are described. Fin structures for finFETs may be formed using two epitaxial layers of different lattice constants that are grown over a bulk substrate. A first thin, strained, epitaxial layer may be cut to form strain-relieved base structures for fins. The base structures may be constrained in a strained-relieved state. Fin structures may be epitaxially grown in a second layer over the base structures. The constrained base structures can cause higher amounts of strain to form in the epitaxially-grown fins than would occur for non-constrained base structures.

A method includes forming a semiconductive channel layer on a substrate. A dummy gate is formed on the semiconductive channel layer. Gate spacers are formed on opposite sides of the dummy gate. The dummy gate is removed to form a gate trench between the gate spacers, resulting in the semiconductive channel layer exposed in the gate trench. A semiconductive protection layer is deposited in the gate trench and on the exposed semiconductive channel layer. A top portion of the semiconductive protection layer is oxidized to form an oxidation layer over a remaining portion of the semiconductive protection layer. The oxidation layer is annealed after the top portion of the semiconductive protection layer is oxidized. A gate structure is formed over the semiconductive protection layer and in the gate trench after the oxidation layer is annealed.

Semiconductor structures and fabrication methods are provided. The semiconductor structure includes a substrate including a first region; a first polarization layer on the first region; and a first gate structure on the first polarization layer. A material of the first polarization layer includes a semiconductor compound material containing first polarization atoms.

A semiconductor device may include a semiconductor layer, and a superlattice adjacent the semiconductor layer and including stacked groups of layers. Each group of layers may include stacked base semiconductor monolayers defining a base semiconductor portion, and at least one oxygen monolayer constrained within a crystal lattice of adjacent base semiconductor portions. The at least one oxygen monolayer of a given group of layers may include an atomic percentage of .sup.18O greater than 10 percent.

The present disclosure describes a 2D channel FET with low contact resistance and a method for forming such a structure. The method includes depositing a dielectric layer on a semiconductor substrate, depositing a metal layer on the dielectric layer, and depositing a hard mask layer on the metal layer. The method further includes forming a gate opening by removing a portion of the hard mask layer and a portion of the metal layer. The method further includes depositing a spacer material layer on sidewalls of the gate opening and forming a channel, the channel including a TMC layer, at a bottom of the gate opening. The method further includes forming a gate structure on the channel and in the gate opening and removing the hard mask layer.

Methods and structures for forming strained-channel finFETs are described. Fin structures for finFETs may be formed in two epitaxial layers that are grown over a bulk substrate. A first thin epitaxial layer may be cut and used to impart strain to an adjacent channel region of the finFET via elastic relaxation. The structures exhibit a preferred design range for increasing induced strain and uniformity of the strain over the fin height.

A FinFET device and a method of forming the same are provided. The method includes forming semiconductor strips over a substrate. Isolation regions are formed over the substrate and between adjacent semiconductor strips. A first recess process is performed on the isolation regions to expose first portions of the semiconductor strips. The first portions of the semiconductor strips are reshaped to form reshaped first portions of the semiconductor strips. A second recess process is performed on the isolation regions to expose second portions of the semiconductor strips below the reshaped first portions of the semiconductor strips. The second portions of the semiconductor strips are reshaped to form reshaped second portions of the semiconductor strips. The reshaped first portions of the semiconductor strips and the reshaped second portions of the semiconductor strips form fins. The fins extend away from topmost surfaces of the isolation regions.

A semiconductor device may include a semiconductor fin, a source/drain region extending from the semiconductor fin, and a gate electrode over the semiconductor fin. The semiconductor fin may include a first well and a channel region over the first well. The first well may have a first dopant at a first dopant concentration and the channel region may have the first dopant at a second dopant concentration smaller than the first dopant concentration. The first dopant concentration may be in range from 10.sup.17 atoms/cm.sup.3 to 10.sup.19 atoms/cm.sup.3.

A method of forming a semiconductor structure includes forming an opening in a dielectric layer, forming a recess in an exposed part of a substrate, and forming a lattice-mismatched crystalline semiconductor material in the recess and opening.