A technique of reducing the manufacturing cost of a semiconductor device is provided, There is provided a method of manufacturing a semiconductor device comprising an ion implantation process of implanting at least one of magnesium and beryllium by ion implantation into a first semiconductor layer that is mainly formed from a group III nitride; and a heating process of heating the first semiconductor layer in an atmosphere that includes an anneal gas of at least one of magnesium and beryllium, after the ion implantation process.

A semiconductor device having a field-effect transistor, including a trench in a semiconductor substrate, a first insulating film in the trench, an intrinsic polycrystalline silicon film over the first insulating film, and first conductivity type impurities in the intrinsic polycrystalline silicon film to form a first conductive film. The first conductive film is etched to form a first gate electrode in the trench. A second insulating film is also formed in the trench above the first insulating film and the first gate electrode, and a first conductivity type doped polycrystalline silicon film, having higher impurity concentration than the first gate electrode is formed over the second insulating film. The doped polycrystalline silicon film is provided in an upper part of the trench to form a second gate electrode.

A semiconductor device includes a semiconductor substrate comprising a main surface and a gate electrode in a trench between neighboring semiconductor mesas, The gate electrode is electrically insulated from the neighboring semiconductor mesas by a dielectric layer. The semiconductor device further includes a conductor arranged, at least partially, between neighboring dielectric contact spacers. The conductor has a conductivity greater than a conductivity of the gate electrode, An interface between the conductor and the gate electrode extends along the gate electrode.

An SiC semiconductor device has a p type region including a low concentration region and a high concentration region filled in a trench formed in a cell region. A p type column is provided by the low concentration region, and a p.sup.+ type deep layer is provided by the high concentration region. Thus, since a SJ structure can be made by the p type column and the n type column provided by the n type drift layer, an on-state resistance can be reduced. As a drain potential can be blocked by the p.sup.+ type deep layer, at turnoff, an electric field applied to the gate insulation film can be alleviated and thus breakage of the gate insulation film can be restricted. Therefore, the SiC semiconductor device can realize the reduction of the on-state resistance and the restriction of breakage of the gate insulation film.

A wide band gap semiconductor device includes a semiconductor layer, a trench formed in the semiconductor layer, first, second, and third regions having particular conductivity types and defining sides of the trench, and a first electrode embedded inside an insulating film in the trench. The second region integrally includes a first portion arranged closer to a first surface of the semiconductor layer than to a bottom surface of the trench, and a second portion projecting from the first portion toward a second surface of the semiconductor layer to a depth below a bottom surface of the trench. The second portion of the second region defines a boundary surface with the third region, the boundary region being at an incline with respect to the first surface of the semiconductor layer.

A semiconductor device according to an embodiment includes a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type, a third semiconductor layer of the first conductivity type, a fourth semiconductor layer of the second conductivity type, a first electrode connected to the second semiconductor layer and the fourth semiconductor layer, a second electrode facing the second semiconductor layer with an insulating film interposed, a fifth semiconductor layer of the second conductivity type, a sixth semiconductor layer of the first conductivity type, a seventh semiconductor layer of the second conductivity type, a third electrode connected to the fifth semiconductor layer and the seventh semiconductor layer, and a fourth electrode facing the fifth semiconductor layer with an insulating film interposed.

Embodiments of the present disclosure provide a self-aligned contact for a trench power MOSFET device. The device has a layer of nitride provided over the conductive material in the gate trenches and over portions of mesas between every two adjacent contact structures. Alternatively, the device has an oxide layer over the conductive material in the gate trenches and over portions of mesas between every two adjacent contact structures. It is emphasized that this abstract is provided to comply with rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

Provided in the present invention is a trench gate power MOSFET (TMOS/UMOS) structure with a heavily doped polysilicon source region. The polysilicon source region is formed by deposition, and a trench-shaped contact hole is used at the source region, in order to attain low contact resistance and small cell pitch. The present invention may also be implemented in an IGBT.

A method for manufacturing a semiconductor device is provided. The method includes operations below. First, an epitaxial layer is formed on a substrate. Then, a trench is formed in the epitaxial layer. Then, a first dielectric layer and a shield layer are formed in the trench, in which the shield layer is embedded within the first dielectric layer. Then, a spacer layer is formed in the trench and on the first dielectric layer. Finally, a second dielectric layer and a gate are formed in the trench and on the spacer layer, and a source is formed in the epitaxial layer surrounding the trench, in which the gate is embedded within the second dielectric layer, and the source surrounds the gate.

First and second cell trench structures extend from a first surface into a semiconductor substrate. The first cell trench structure includes a first buried electrode and a first insulator layer between the first buried electrode and a semiconductor mesa separating the first and second cell trench structures. A capping layer covers the first surface. The capping layer is patterned to form an opening having a minimum width larger than a thickness of the first insulator layer. The opening exposes a first vertical section of the first insulator layer at the first surface. An exposed portion of the first insulator layer is removed to form a recess between the semiconductor mesa and the first buried electrode. A contact structure is in the opening and the recess. The contact structure electrically connects both a buried zone in the semiconductor mesa and the first buried electrode and allows for narrower semiconductor mesa width.