A semiconductor device includes: a semiconductor layer of silicon carbide including a plurality of layers disposed on a main surface side; an electrode layer that is one of the plurality of layers, wherein the electrode layer has an electrode connecting surface to which a conductive connecting member is connected, and the electrode layer is composed mainly of silver; and a first metal layer that is a layer, different from the electrode layer, among the plurality of layers, wherein the first metal layer has a first bonding surface bonded onto the electrode layer such that the electrode connecting surface is exposed to an outside, and a second bonding surface electrically connected to the semiconductor layer, and the first metal layer is composed mainly of titanium carbide.

A semiconductor device according to an embodiment includes a first electrode; a second electrode; a silicon carbide layer disposed between the first electrode and the second electrode; a first n-type silicon carbide region disposed in the silicon carbide layer; and a first nitrogen region disposed in the silicon carbide layer, the first nitrogen region disposed between the first n-type silicon carbide region and the first electrode, and the first nitrogen region having a first nitrogen concentration higher than a first n-type impurity concentration of the first n-type silicon carbide region.

Along dicing lines, cutting grooves that reach a rear surface from a front surface are formed by a first dicing blade in a semiconductor wafer, completely separating the semiconductor wafer into individual semiconductor chips by the cutting grooves. Thereafter, by a second dicing blade that is constituted by abrasive grains having a mean grit size smaller than that of the first dicing blade and that has a blade width wider than that of the first dicing blade, side walls of the cutting grooves, i.e., side surfaces of the semiconductor chips are polished, approaching a specular state.

A method for manufacturing a SiC mixed trench Schottky diode may include steps of providing a substrate and an epitaxial layer on top of the substrate; forming a plurality of trenches on a surface of the epitaxial layer; conducting ion implantation at a bottom portion of each trench; conducting ion implantation at sidewalls of each trench; forming an ohmic contact metal at a bottom portion of the Schottky diode; forming a Schottky contact metal on top of the epitaxial layer and in the trenches. In one embodiment, the substrate is an N.sup.+ type SiC and the epitaxial layer is an N.sup. type SiC. In another embodiment, the step of forming a plurality of trenches on a surface of the epitaxial layer may include the step of etching the surface of the epitaxial layer by either dry etching or wet etching.

A semiconductor device includes a semiconductor layer including first and second electrode forming surfaces and side surface, an anode electrode formed on the first electrode forming surface, a cathode electrode formed on the second electrode forming surface; an insulating film continuously formed from the first electrode forming surface to the side surface so as to cover the first edge. The side surface of the semiconductor layer is covered with the insulating film, so that a leak current flowing along the side surface is reduced. Further, the side surface is protected by the insulating film, making cracking, chipping, cleavage, and the like less likely to occur.

The present invention relates to a silicon carbide trench Schottky barrier diode using polysilicon and a method of manufacturing same. The diode has a low turn-on voltage and an improved reverse characteristic. The method includes sequentially forming an epitaxial layer, a polysilicon layer, an oxide film, and a photoresist film on a silicon carbide substrate, patterning the photoresist to form a photoresist pattern, etching the oxide film using the photoresist pattern as an etching mask to form an oxide film pattern, etching the polysilicon layer using the oxide film pattern as an etching mask to form a polysilicon pattern, removing the photoresist pattern, forming an epitaxial pattern by etching the epitaxial layer down to a predetermined depth using the oxide film pattern as an etching mask, and removing the oxide film pattern to produce a trench.

An n-type GaN layer, a p-type diffusion region formed by ion implantation and annealing in a part of the n-type layer, and a Schottky electrode are formed on the n-type layer. A region without the p-type region is defined as region A, and a region with the p-type region is defined as region B. In region A, an average density of each electron trap level of the n-type layer in a region having a depth of 0.8 m to 1.6 m on the n-type layer side is set so as to satisfy the predetermined conditions. In region B, an average density of each carrier trap level of the n-type layer in a region having a depth of 0.8 m to 1.6 m on the n-type layer side from a boundary between the n-type layer and the p-type diffusion region is set so as to satisfy the predetermined conditions.

In forming an ohmic electrode on a back surface of an n-type SiC substrate, an n.sup.+-type semiconductor region is formed in a surface layer of the back surface of an n-type epitaxial substrate by ion implantation. In this ion implantation, the impurity concentration of the n.sup.+-type semiconductor region is a predetermined range and preferably a predetermined value or less, and an n-type impurity is implanted by acceleration energy of a predetermined range such that the n.sup.+-type semiconductor region has a predetermined thickness or less. Thereafter, a nickel layer and a titanium layer are sequentially formed on the surface of the n.sup.+-type semiconductor region, the nickel layer is heat treated to form a silicide, and the ohmic electrode formed from nickel silicide is formed. In this manner, a back surface electrode that has favorable properties can be formed while peeling of the back surface electrode can be suppressed.

A semiconductor device according to the present invention includes a first conductive-type SiC semiconductor layer, and a Schottky metal, comprising molybdenum and having a thickness of 10 nm to 150 nm, that contacts the surface of the SiC semiconductor layer. The junction of the SiC semiconductor layer to the Schottky metal has a planar structure, or a structure with recesses and protrusions of equal to or less than 5 nm.

A silicon carbide semiconductor device includes a silicon carbide semiconductor substrate of a first conductivity type, a first silicon carbide layer of the first conductivity type, and an insulating film. In the silicon carbide semiconductor device, no fluorine or chlorine is detectable in the insulating film, at a boundary layer of the insulating film and the first silicon carbide layer, or at the surface of first silicon carbide layer where the insulating film is provided.