A transistor comprises a semiconductor substrate and a barrier metal layer forming a Schottky barrier. One or more insulated gates may be positioned adjacent to an edge of the Schottky barrier. By applying a reverse bias voltage between the semiconductor substrate and the barrier metal, and applying a gate voltage between the one or more insulated gates and the barrier metal, a reverse bias current may be increased to a reverse bias conducting state. When the gate voltage is sufficient, the transistor may conduct current between the semiconductor substrate and the barrier metal. For example, voltages may be applied to an n-type substrate and an insulated gate (both relative to the barrier metal), and a current may flow from the semiconductor substrate to the barrier metal. The transistor may operate as a switch, a filter, a rectifier, an oscillator, or an amplifier.

A trench metal-oxide-semiconductor field-effect transistor (MOSFET) device comprises an active cell area including a plurality of superjunction trench power MOSFETs, and a Schottky diode area including a plurality of Schottky diodes formed in the drift region having the superjunction structure. Each of the integrated Schottky diodes includes a Schottky contact between a lightly doped semiconductor layer and a metallic layer.

A trench metal-oxide-semiconductor field-effect transistor (MOSFET) device comprises an active cell area including a plurality of superjunction trench power MOSFETs, and a Schottky diode area including a plurality of Schottky diodes formed in the drift region having the superjunction structure. Each of the integrated Schottky diodes includes a Schottky contact between a lightly doped semiconductor layer and a metallic layer.

[Object] To provide a semiconductor device capable of improving a discharge starting voltage when measuring electric characteristics, and widening a pad area of a surface electrode or increasing the number of semiconductor devices (number of chips) to be obtained from one wafer, and a method for manufacturing the same.

[Solution Means] A semiconductor device 1 includes an n-type SiC layer 2 having a first surface 2A, a second surface 2B, and end faces 2C, a p-type voltage relaxing layer 7 formed in the SiC layer 2 so as to be exposed to the end portion of the first surface 2A of the SiC layer 2, an insulating layer 8 formed on the SiC layer 2 so as to cover the voltage relaxing layer 7, and an anode electrode 9 that is connected to the first surface 2A of the SiC layer 2 through the insulating layer 8 and has a pad area 95 selectively exposed.

[Object] To provide a semiconductor device capable of improving a discharge starting voltage when measuring electric characteristics, and widening a pad area of a surface electrode or increasing the number of semiconductor devices (number of chips) to be obtained from one wafer, and a method for manufacturing the same.

[Solution Means] A semiconductor device 1 includes an n-type SiC layer 2 having a first surface 2A, a second surface 2B, and end faces 2C, a p-type voltage relaxing layer 7 formed in the SiC layer 2 so as to be exposed to the end portion of the first surface 2A of the SiC layer 2, an insulating layer 8 formed on the SiC layer 2 so as to cover the voltage relaxing layer 7, and an anode electrode 9 that is connected to the first surface 2A of the SiC layer 2 through the insulating layer 8 and has a pad area 95 selectively exposed.

Disclosed is a cellular structure of a silicon carbide MOSFET device, and a silicon carbide MOSFET device. The cellular structure comprises: second conductive well regions located on two sides of the cellular structure and arranged within the surface of a drift layer, first conductive source regions located within the surfaces of the well regions, and a gate structure located at the center of the cellular structure and in contact with the source regions, the well regions, and the drift layer. The cellular structure further comprises a source metal layer located above the source regions and forming ohmic contact with the source regions; on two sides of the cellular structure, side trenches are formed downwardly on regions of the drift layer that are not covered by the well regions; Schottky metal layers forming Schottky contact with the drift layer below the side trenches are arranged in the side trenches.

Disclosed is a cellular structure of a silicon carbide MOSFET device, and a silicon carbide MOSFET device. The cellular structure comprises: second conductive well regions located on two sides of the cellular structure and arranged within the surface of a drift layer, first conductive source regions located within the surfaces of the well regions, and a gate structure located at the center of the cellular structure and in contact with the source regions, the well regions, and the drift layer. The cellular structure further comprises a source metal layer located above the source regions and forming ohmic contact with the source regions; on two sides of the cellular structure, side trenches are formed downwardly on regions of the drift layer that are not covered by the well regions; Schottky metal layers forming Schottky contact with the drift layer below the side trenches are arranged in the side trenches.

A cell structure of a silicon carbide MOSFET device, comprising a first conductivity type drift region (3) located above a first conductivity type substrate (2). A main trench is provided in the surface of the first conductivity type drift region (3); a Schottky metal (4) is provided on the bottom and sidewalls of the main trench; a second conductivity type well region (7) is provided in the surface of the first conductivity type drift region (3) and around the main trench; a source region (8) is provided in the surface of the well region (7); a source metal (10) is provided above the source region (8); a gate insulating layer (6) and a gate (5) split into two parts are provided above the sides of the source region (8), the well region (7), and the first conductivity type drift region (3) close to the main trench.

A silicon carbide semiconductor device is a SiC-SBD that has, in an active region, at a front surface of a semiconductor substrate containing silicon carbide, a mixture of a SBD structure having Schottky barrier junctions between a titanium film that is a lowermost layer of a front electrode and an n.sup.−-type drift region, and a JBS structure having pn junction portions between p-type regions and the n.sup.−-type drift region. The p-type regions form ohmic junctions with the titanium film that is the lowermost layer of the front electrode. After an ion implantation for the p-type regions, activation annealing is performed at a temperature in a range of 1700 degrees C. to 1900 degrees C. for a treatment time exceeding 20 minutes, whereby contact resistance between the titanium film and the p-type regions is adjusted to be in a range of about 5×10.sup.−4 Ω.Math.cm.sup.2 to 8×10.sup.−3 Ω.Math.cm.sup.2.

A silicon carbide semiconductor device is a SiC-SBD that has, in an active region, at a front surface of a semiconductor substrate containing silicon carbide, a mixture of a SBD structure having Schottky barrier junctions between a titanium film that is a lowermost layer of a front electrode and an n.sup.−-type drift region, and a JBS structure having pn junction portions between p-type regions and the n.sup.−-type drift region. The p-type regions form ohmic junctions with the titanium film that is the lowermost layer of the front electrode. After an ion implantation for the p-type regions, activation annealing is performed at a temperature in a range of 1700 degrees C. to 1900 degrees C. for a treatment time exceeding 20 minutes, whereby contact resistance between the titanium film and the p-type regions is adjusted to be in a range of about 5×10.sup.−4 Ω.Math.cm.sup.2 to 8×10.sup.−3 Ω.Math.cm.sup.2.