Patent ID: 11929400
Assignee: FUJI ELECTRIC CO., LTD.
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A method of manufacturing a silicon carbide semiconductor device, the method comprising:
forming a first-conductivity-type region in a semiconductor substrate containing silicon carbide, a surface of the first-conductivity-type region constituting a first main surface of the semiconductor substrate, a second main surface of the semiconductor substrate being opposite to the first main surface thereof;
selectively forming a plurality of second-conductivity-type regions in the first-conductivity-type region, at the first main surface of the semiconductor substrate;
forming, on the first main surface of the semiconductor substrate, an interlayer insulating film covering the first-conductivity-type region and the second-conductivity-type regions;
selectively removing the interlayer insulating film to form a plurality of openings exposing the second-conductivity-type regions;
forming, in each of the openings of the interlayer insulating film, a layered metal film, to thereby have an aluminum film in contact with the first main surface of the semiconductor substrate and a cap film stacked on the aluminum film to cover the aluminum film;
thermally diffusing aluminum atoms in the aluminum film, from a contact portion between the aluminum film and the semiconductor substrate, to the second-conductivity-type regions by a heat treatment, to thereby form a plurality of second-conductivity-type high-concentration regions, each second-conductivity-type high-concentration region being formed in a surface region of one of the second-conductivity-type regions, and having an impurity concentration higher than an impurity concentration of said one second-conductivity-type regions;
removing the layered metal film after forming the second-conductivity-type high-concentration regions;
selectively removing the interlayer insulating film to form a contact hole, after removing the layered metal film;
forming a first electrode by sequentially stacking a titanium film and a metal film containing aluminum on the first surface of the semiconductor substrate in the contact hole, the titanium film being in contact with the first-conductivity-type region and forming Schottky junctions with the first-conductivity-type region, the titanium film being in contact with the second-conductivity-type high-concentration regions and forming ohmic contacts with the second-conductivity-type high-concentration regions; and
forming a second electrode on the second main surface of the semiconductor substrate.