A gate insulating film and a gate electrode of non-single crystalline silicon for forming an nMOS transistor are provided on a silicon substrate. Using the gate electrode as a mask, n-type dopants having a relatively large mass number (70 or more) such as As ions or Sb ions are implanted, to form a source/drain region of the nMOS transistor, whereby the gate electrode is amorphized. Subsequently, a silicon oxide film is provided to cover the gate electrode, at a temperature which is less than the one at which recrystallization of the gate electrode occurs. Thereafter, thermal processing is performed at a temperature of about 1000 C., whereby high compressive residual stress is exerted on the gate electrode, and high tensile stress is applied to a channel region under the gate electrode. As a result, carrier mobility of the nMOS transistor is enhanced.

Some embodiments include a transistor having a first electrically conductive gate portion along a first segment of a channel region and a second electrically conductive gate portion along a second segment of the channel region. The second electrically conductive gate portion is a different composition than the first electrically conductive gate portion. Some embodiments include a method of forming a semiconductor construction. First semiconductor material and metal-containing material are formed over a NAND string. An opening is formed through the metal-containing material and the first semiconductor material, and is lined with gate dielectric. Second semiconductor material is provided within the opening to form a channel region of a transistor. The transistor is a select device electrically coupled to the NAND string.

A semiconductor device of the present invention includes a semiconductor layer in which a gate trench is formed, a gate insulating film formed along an inner surface of the gate trench, a gate electrode that is buried in the gate trench through the gate insulating film and that has a lower electrode and an upper electrode that are separated upwardly and downwardly from each other with an intermediate insulating film between the lower electrode and the upper electrode, and a gate contact that is formed in the gate trench so as to pass through the upper electrode and through the intermediate insulating film and so as to reach the lower electrode and that electrically connects the lower electrode and the upper electrode together.

A semiconductor device of the present invention includes a semiconductor layer of a first conductivity type having a cell portion and an outer peripheral portion disposed around the cell portion, and a surface insulating film disposed in a manner extending across the cell portion and the outer peripheral portion, and in the cell portion, formed to be thinner than a part in the outer peripheral portion.

A semiconductor device includes a semiconductor region made of a material to which conductive impurities are added, an insulating film formed on a surface of the semiconductor region, and an electroconductive gate electrode formed on the insulating film. The gate electrode is made of a material whose Fermi level is closer to a Fermi level of the semiconductor region than a Fermi level of Si in at least a portion contiguous to the insulating film.

A nonvolatile semiconductor memory device includes a charge storage layer on a first insulating film, a second insulating film which is provided on the charge storage layer, formed of layers, and a control gate electrode on the second insulating film. The second insulating film includes a bottom layer (A) provided just above the charge storage layer, a top layer (C) provided just below the control gate electrode, and a middle layer (B) provided between the bottom layer (A) and the top layer (C). The middle layer (B) has higher barrier height and lower dielectric constant than both the bottom layer (A) and the top layer (C). The average coordination number of the middle layer (B) is smaller than both the average coordination number of the top layer (C) and the average coordination number of the bottom layer (A).

A semiconductor device of the present invention includes a semiconductor layer of a first conductivity type having a cell portion and an outer peripheral portion disposed around the cell portion, formed with a gate trench at a surface side of the cell portion, and a gate electrode buried in the gate trench via a gate insulating film, forming a channel at a portion lateral to the gate trench at ON-time, the outer peripheral portion has a semiconductor surface disposed at a depth position equal to or deeper than a depth of the gate trench, and the semiconductor device further includes a voltage resistant structure having a semiconductor region of a second conductivity type formed in the semiconductor surface of the outer peripheral portion.

A semiconductor device includes a vertical power transistor having a plurality of power transistor cells. Each power transistor cell includes a source region at a first main surface of a semiconductor substrate, a drain region at a second main surface of the semiconductor substrate opposite the first main surface, a gate trench extending into the semiconductor substrate from the first main surface, a gate electrode in the gate trench and comprising doped polycrystalline silicon, and a dielectric material separating the gate electrode from the semiconductor substrate. An upper central part of each of the gate electrodes of the power transistor cells is occupied by a metal silicide region that adjoins the doped polycrystalline silicon. A method of producing the semiconductor device is also described.

The disclosure relates to a semiconductor device having a gate electrode in a vertical gate trench and a channel region laterally aside the gate trench. The gate electrode includes an outer gate region made of an outer gate material, a metal inlay region made of a metal material, and a spacer region. The outer gate material and the spacer region are each different from the metal material. The spacer region, the metal inlay region, and the outer gate region are, at least in a vertical section of the gate electrode, consecutively arranged from a center position within the gate electrode laterally outwardly towards the channel region.

A gate insulating film and a gate electrode of non-single crystalline silicon for forming an nMOS transistor are provided on a silicon substrate. Using the gate electrode as a mask, n-type dopants having a relatively large mass number (70 or more) such as As ions or Sb ions are implanted, to form a source/drain region of the nMOS transistor, whereby the gate electrode is amorphized. Subsequently, a silicon oxide film is provided to cover the gate electrode, at a temperature which is less than the one at which recrystallization of the gate electrode occurs. Thereafter, thermal processing is performed at a temperature of about 1000 C., whereby high compressive residual stress is exerted on the gate electrode, and high tensile stress is applied to a channel region under the gate electrode. As a result, carrier mobility of the nMOS transistor is enhanced.