A semiconductor device includes a substrate including a plurality of transistor devices formed thereon, at least an epitaxial structure formed in between the transistor devices, and a tri-layered structure formed on the epitaxial structure. The epitaxial structure includes a first semiconductor material and a second semiconductor material, and a lattice constant of the second semiconductor material is larger than a lattice constant of the first semiconductor material. The tri-layered structure includes an undoped epitaxial layer, a metal-semiconductor compound layer, and a doped epitaxial layer sandwiched in between the undoped epitaxial layer and the metal-semiconductor compound layer. The undoped epitaxial layer and the doped epitaxial layer include at least the second semiconductor material.

A method for manufacturing a semiconductor substrate may comprise irradiating a surface of a first semiconductor layer and a surface of a second semiconductor layer with one or more types of first impurity in a vacuum. The method may comprise bonding the surface of the first semiconductor layer and the surface of the second semiconductor layer to each other in the vacuum. The method may comprise applying heat treatment to the semiconductor substrate produced in the bonding. The first impurity may be an inert impurity that does not generate carriers in the first and second semiconductor layers. The heat treatment may be applied such that a width of an in-depth concentration profile of the first impurity contained in the first and second semiconductor layers is narrower after execution of the heat treatment than before the execution of the heat treatment.

An integrated circuit which includes a field-plated FET is formed by forming a first opening in a layer of oxide mask, exposing an area for a drift region. Dopants are implanted into the substrate under the first opening. Subsequently, dielectric sidewalls are formed along a lateral boundary of the first opening. A field relief oxide is formed by thermal oxidation in the area of the first opening exposed by the dielectric sidewalls. The implanted dopants are diffused into the substrate to form the drift region, extending laterally past the layer of field relief oxide. The dielectric sidewalls and layer of oxide mask are removed after the layer of field relief oxide is formed. A gate is formed over a body of the field-plated FET and over the adjacent drift region. A field plate is formed immediately over the field relief oxide adjacent to the gate.

An integrated circuit which includes a field-plated FET is formed by forming a first opening in a layer of oxide mask, exposing an area for a drift region. Dopants are implanted into the substrate under the first opening. Subsequently, dielectric sidewalls are formed along a lateral boundary of the first opening. A field relief oxide is formed by thermal oxidation in the area of the first opening exposed by the dielectric sidewalls. The implanted dopants are diffused into the substrate to form the drift region, extending laterally past the layer of field relief oxide. The dielectric sidewalls and layer of oxide mask are removed after the layer of field relief oxide is formed. A gate is formed over a body of the field-plated FET and over the adjacent drift region. A field plate is formed immediately over the field relief oxide adjacent to the gate.

Techniques for forming Ga-doped source drain contacts in Ge-based transistors are provided. In one aspect, a method for forming Ga-doped source and drain contacts includes the steps of: depositing a dielectric over a transistor; depositing a dielectric over the transistor; forming contact trenches in the dielectric over, and extending down to, source and drain regions of the transistor; depositing an epitaxial material into the contact trenches; implanting gallium ions into the epitaxial material to form an amorphous gallium-doped layer; and annealing the amorphous gallium-doped layer under conditions sufficient to form a crystalline gallium-doped layer having a homogenous gallium concentration of greater than about 510.sup.20 at./cm.sup.3. Transistor devices are also provided utilizing the present Ga-doped source and drain contacts.

A method for making a semiconductor device may include forming a plurality of stacked groups of layers on a semiconductor substrate, with each group of layers including a plurality of 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 implanting a dopant in the semiconductor substrate beneath the plurality of stacked groups of layers in at least one localized region, and performing an anneal of the plurality of stacked groups of layers and semiconductor substrate and with the plurality of stacked groups of layers vertically and horizontally constraining the dopant in the at least one localized region.

A semiconductor device includes a first semiconductor region of a first conductivity type, a second semiconductor region of a second conductivity type provided on a part of the first semiconductor region, a third semiconductor region of the first conductivity type provided on a part of the second semiconductor region, agate electrode, a first electrode, and a conductive portion. The gate electrode is provided on another part of the second semiconductor region via a gate insulating portion. The first electrode is provided on the third semiconductor region and electrically connected to the third semiconductor region. The conductive portion is provided on another part of the first semiconductor region via a first insulating portion and electrically connected to the first electrode, and includes a portion arranged side by side with the gate electrode in a second direction perpendicular to a first direction from the first semiconductor region to the first electrode.

A semiconductor device according to the present invention includes a semiconductor substrate, having an emitter layer of a first conductivity type, a collector layer of a second conductivity type and a drift layer of the first conductivity type sandwiched therebetween, the emitter layer disposed at a front surface side of the semiconductor substrate and the collector layer disposed at a rear surface side of the semiconductor substrate, a base layer of the second conductivity type between the drift layer and the emitter layer, a buffer layer of the first conductivity type between the collector layer and the drift layer, the buffer layer having an impurity concentration higher than that of the drift layer, and having an impurity concentration profile with two peaks in regard to a depth direction from the rear surface of the semiconductor substrate, and a defect layer, formed in the drift layer and having an impurity concentration profile with a half-value width of not more than 2 m in regard to the depth direction from the rear surface of the semiconductor substrate.

The present invention provides a semiconductor element that can be manufactured easily at a low cost, can obtain a high tunneling current, and has an excellent operating characteristic, a method for manufacturing the same, and a semiconductor integrated circuit including the semiconductor element. The semiconductor element of the present invention is characterized in that the whole or a part of a tunnel junction is constituted by a semiconductor region made of an indirect-transition semiconductor containing isoelectronic-trap-forming impurities.

A method for forming a semiconductor device includes blocking a first region of a wafer and forming a plurality of fins in a second region of the wafer. A protective conformal mask layer is deposited over the plurality of fins in the second region, the second region is blocked, and a plurality of fins are formed in the first region of the wafer using a variety of wet and/or dry etching procedures. The protective conformal mask layer protects the plurality of fins in the second region from the variety of wet and/or dry etching procedures that are used to form the plurality of fins in the first region.