An insulated gate semiconductor device includes: a carrier transport layer of a first conductivity-type; an injection control region of a second conductivity-type; a carrier supply region of the first conductivity-type; a base contact region of the second conductivity-type; trenches penetrating the injection control region to reach the carrier transport layer; an insulated gate structure provided inside the respective trenches; an upper buried region of the second conductivity-type being in contact with a bottom surface of the injection control region; a lower buried region of the second conductivity-type being in contact with a bottom surface of the upper buried region and a bottom surface of the respective trenches; and a high-concentration region of the first conductivity-type provided inside the carrier transport layer to be in contact with a part of a bottom surface of the lower buried region.

A semiconductor device of embodiments includes: an electrode containing titanium (Ti); a silicon carbide layer; a first region provided between the silicon carbide layer and the electrode, containing silicon (Si) and oxygen (O), and having a thickness equal to or more than 2 nm and equal to or less than 10 nm; and a second region provided between the first region and the electrode and containing titanium (Ti) and silicon (Si).

The present invention addresses the problem of providing novel techniques for manufacturing a SiC substrate that enables reduced material loss when a strained layer is removed. The present invention is a method for manufacturing a SiC substrate 30 which includes a strained layer thinning step S1 for thinning a strained layer 12 of a SiC substrate body 10 by moving the strained layer 12 to a surface side. Including such a strained layer thinning step S1 in which the strain layer is moved to (concentrated toward) the surface side makes it possible to reduce material loss L when removing the strained layer 12.

A nano-FET and a method of forming is provided. In some embodiments, a nano-FET includes an epitaxial source/drain region contacting ends of a first nanostructure and a second nanostructure. The epitaxial source/drain region may include a first semiconductor material layer of a first semiconductor material, such that the first semiconductor material layer includes a first segment contacting the first nanostructure and a second segment contacting the second nanostructure, wherein the first segment is separated from the second segment. A second semiconductor material layer is formed over the first segment and the second segment. The second semiconductor material layer may include a second semiconductor material having a higher concentration of dopants of a first conductivity type than the first semiconductor material layer. The second semiconductor material layer may have a lower concentration percentage of silicon than the first semiconductor material layer.

A drift layer is formed over a semiconductor substrate which is an SiC substrate. The drift layer includes first to third n-type semiconductor layers and a p-type impurity region. Herein, an impurity concentration of the second n-type semiconductor layer is higher than an impurity concentration of the first n-type semiconductor layer and an impurity concentration of the third n-type semiconductor layer. Also, in plan view, the second semiconductor layer located between the p-type impurity regions adjacent to each other overlaps with at least a part of a gate electrode formed in a trench.

A substrate is mounted on a rotator provided in a reaction chamber, while a first process gas containing no source gas is supplied to an upper surface of the substrate from above the substrate and the substrate is rotated at 300 rpm or more, a temperature of a wall surface is changed, and after a temperature of the substrate is allowed to rise, the substrate is controlled to a predetermined film formation temperature and a second process gas containing a source gas is supplied to the upper surface of the substrate from above the substrate to grow an SiC film on the substrate.

In a silicon carbide substrate including: a SiC substrate; and a first semiconductor layer, a second semiconductor layer and a drift layer that are epitaxial layers sequentially formed on the SiC substrate, an impurity concentration of the first semiconductor layer is lower than impurity concentrations of the SiC substrate and the second semiconductor layer, and the second semiconductor layer is formed to have a high impurity concentration or a large thickness.

A semiconductor device of embodiments includes: a silicon carbide layer having a first face having an off angle equal to or more than 0° and equal to or less than 8° with respect to a {0001} face and a second face facing the first face and having a 4H-SiC crystal structure; a gate electrode extending in a first direction parallel to the first face; a silicon oxide layer between the silicon carbide layer and the gate electrode; and a region disposed between the silicon carbide layer and the silicon oxide layer and having a nitrogen concentration equal to or more than 1 × 10.sup.21 cm.sup.-3. Assuming that a first reference length in the first direction is 0.5 .Math.m, a surface roughness of a surface of the silicon carbide layer in a range of the first reference length is equal to or less than 1 nm.

A method for manufacturing a compound semiconductor substrate comprises: a step to form an SiC (silicon carbide) layer on a Si (silicon) substrate, a step to form a LT (Low Temperature)-AlN (aluminum nitride) layer with a thickness of 12 nanometers or more and 100 nanometers or less on the SiC layer at 700 degrees Celsius or more and 1000 degrees Celsius or less, a step to form a HT (High Temperature)-AlN layer on the LT-AlN layer at a temperature higher than the temperature at which the LT-AlN layer was formed, a step to form an Al (aluminum) nitride semiconductor layer on the HT-AlN layer, a step to form a GaN (gallium nitride) layer on the Al nitride semiconductor layer, and a step to form an Al nitride semiconductor layer on the GaN layer.

A semiconductor device includes: an inversion type semiconductor element that includes: a substrate having a first conductivity type or a second conductivity type; a first conductivity type layer formed on the substrate; a second conductivity type region that is formed on the first conductivity type layer; a JFET portion that is formed on the first conductivity type layer, is sandwiched by the second conductivity type region to be placed; a source region that is formed on the second conductivity region; a gate insulation film formed on a channel region that is a part of the second conductivity type region; a gate electrode formed on the gate insulation film; an interlayer insulation film covering the gate electrode and the gate insulation film, and including a contact hole; a source electrode electrically connected to the source region through the contact hole; and a drain electrode formed on a back side of the substrate.