An SiC semiconductor device includes an SiC semiconductor layer including an SiC monocrystal that is constituted of a hexagonal crystal and having a first main surface as a device surface facing a c-plane of the SiC monocrystal and has an off angle inclined with respect to the c-plane, a second main surface at a side opposite to the first main surface, and a side surface facing an a-plane of the SiC monocrystal and has an angle less than the off angle with respect to a normal to the first main surface when the normal is 0°.

In a silicon carbide semiconductor device in which a contact electrode is formed on a single-crystal silicon carbide semiconductor substrate, a barrier metal (titanium nitride layer) covers an interlayer insulating film in a region other than a contact hole, and a contact electrode of a predetermined electrode material is formed only in a region on the silicon carbide semiconductor substrate in the contact hole opened in the interlayer insulating film on the silicon carbide semiconductor substrate. A top of the barrier metal is covered by a metal electrode (wiring layer) and no nickel metal aggregates are present between the barrier metal and the metal electrode.

A semiconductor device of the present invention includes a semiconductor region having a first main surface, wherein the semiconductor region includes: alternating n-type pillar layers and p-type pillar layers along the first main surface; a p-type first well layer located within each of the n-type pillar layers at a top surface of the n-type pillar layer; an n-type first source layer located within the first well layer at a top surface of the first well layer; a first side surface dielectric layer located on a side surface in a first trench located at each of boundaries between the n-type pillar layers and the p-type pillar layers, and being in contact with the first well layer and the first source layer; a first bottom surface dielectric layer located on a bottom surface in the first trench, and being at least partially in contact with one of the p-type pillar layers.

A power semiconductor device includes an SiC semiconductor layer, a plurality of well regions disposed in the semiconductor layer such that two adjacent well regions at least partially make contact with each other, a plurality of source regions on the plurality of well regions in the semiconductor layer, a drift region in a first conductive type, a plurality of trenches recessed into the semiconductor layer from the surface of the semiconductor layer, a gate insulating layer on an inner wall of each trench, a gate electrode layer disposed on the gate insulating layer and including a first part disposed in each trench and a second part on the semiconductor layer, and a pillar region positioned under the plurality of well regions to make contact with the drift region and the plurality of well regions in the semiconductor layer, and having a second conductive type.

A power semiconductor device includes a semiconductor layer based on silicon carbide (SiC), a vertical drift region positioned to extend in a vertical direction inside the semiconductor layer and having a first conductive type, a well region positioned in at least one side of the vertical drift region to make contact with the vertical drift region and having a second conductive type, recess gate electrodes extending from a surface of the semiconductor layer into the semiconductor layer and buried in the vertical drift region and the well region to cross the vertical drift region and the well region in a first direction, source regions positioned in the well region between the recess gate electrodes and having the first conductive type, and insulating-layer protective regions surrounding lower portions of the recess gate electrodes, respectively, in the vertical drift region, and having the second conductive type.

A method of manufacturing a silicon carbide semiconductor device includes formation of an electrode and formation of a gate wiring. The electrode is formed to be electrically connected to a base layer and an impurity region included in a semiconductor substrate through a first contact hole. The gate wiring is formed to be electrically connected to a connection wiring through a second contact hole, and is made of material capable of deoxidizing an oxide film. The oxide film is removed by deoxidizing the oxide film formed on the connection wiring to remove the oxygen from the oxide film into the gate wiring through heating treatment for the gate wiring in the formation of the gate wiring or after the formation of the gate wiring.

A power device includes a silicon carbide substrate. A gate is provided on a first side of the silicon carbide substrate. A graded channel includes a first region having a first dopant concentration and a second region having a second dopant concentration, the second dopant concentration being greater than the first dopant concentration.

A silicon carbide layer has an active region and an outer peripheral region arranged along an outer periphery of the active region in an in-plane direction. First well regions are arranged in the active region. A second well region is arranged in the outer peripheral region. Ohmic electrodes are arranged on a second surface of the silicon carbide layer, are connected to a source electrode, are electrically and ohmically connected to the first well regions, and have surface regions ohmically contacting a part forming the second surface of the silicon carbide layer and having a second conductivity type. The active region includes a standard region part and a thinned region part between the standard region part and the outer peripheral region. The surface regions are arranged at surface density lower in the thinned region part than in the standard region part in a plan view.

Disclosed is a manufacturing method of a trench-type power device. The manufacturing method comprises: forming a drift region; forming a first trench and a second trench in the drift region; forming a gate stack in the first trench; forming a doped region and a well region of P type in the drift region by performing first ion implantation; forming a source region of N type in the well region by performing second ion implantation. The well region in which a dopant concentration gradually decreases with depth is formed by the first ion implantation, an upper part of the well region is inverted by the second ion implantation to form the source region. The doped region and well region can be formed by self-alignment in a common ion implantation step, improving power device performance, reducing numbers of process steps of ion implantation and masks, reducing manufacturing cost.

Disclosed is a trench-type power device and a manufacturing method thereof. The trench-type power device comprises: a semiconductor substrate; a drift region located on the semiconductor substrate; a first trench and a second trench located in the drift region; a gate stack located in the first trench; and Schottky metal located on a side wall of the second trench, wherein the Schottky metal and the drift region form a Schottky barrier diode. The trench-type power device adopts a double-trench structure, which combines a trench-type MOSFET with the Schottky barrier diode and forms the Schottky metal on the side wall of the trench, so that the performance of the power device can be improved, and the unit area of the power device can be reduced.