Silicon carbide semiconductor element, method of manufacturing the same, and silicon carbide device
View Patent ↗A silicon carbide semiconductor element and a manufacturing method thereof are disclosed in which a low contact resistance is attained between an electrode film and a wiring conductor element, and the wiring conductor element is hardly detached from the electrode film. In the method, a nickel film and a nickel oxide film are laminated in this order on a surface of an n-type silicon carbide substrate or an n-type silicon carbide region of a silicon carbide substrate, followed by a heat treatment under a non-oxidizing condition. The heat treatment transforms a portion of the nickel film into a nickel silicide film. Then, the nickel oxide film is removed with hydrochloric acid solution, and subsequently, a nickel aluminum film and an aluminum film are laminated in this order on a surface of the nickel silicide film.
1. A method of manufacturing a silicon carbide semiconductor element comprising:
forming a nickel film on a surface of an n-type silicon carbide substrate or an n-type silicon carbide region formed on a silicon carbide substrate;
forming a nickel oxide film on a surface of the nickel film; and
heat treating the nickel film in a non-oxidizing atmosphere.
2. The method of manufacturing a silicon carbide semiconductor element according to claim 1 , wherein the non-oxidizing atmosphere is an atmosphere of vacuum or argon.
3. The method of manufacturing a silicon carbide semiconductor element according to claim 1 , wherein a nickel silicide film is formed in a portion of the nickel film during the heat treating.
4. The method of manufacturing a silicon carbide semiconductor element according to claim 3 further comprising, after the heat treating,
removing the nickel oxide film with a hydrochloric acid solution; and
forming an aluminum film on a surface of the nickel silicide film from which the nickel oxide film has been removed.
5. The method of manufacturing a silicon carbide semiconductor element according to claim 3 further comprising
removing the nickel oxide film with a hydrochloric acid solution
forming a nickel aluminum film on a surface of the nickel silicide film after removing the nickel oxide film,
forming an aluminum film on the surface of the nickel aluminum film.
6. The method of manufacturing a silicon carbide semiconductor element according to claim 1 , wherein the nickel film that is formed has a thickness in a range of 0.05 μm to 0.2 μm, and the nickel oxide film that is formed has a thickness in a range of 0.05 μm to 0.15 μm.
7. The method of manufacturing a silicon carbide semiconductor element according to claim 5 , wherein the nickel aluminum film that is formed has a thickness in a range of 5 nm to 20 nm, and the aluminum film that is formed has a thickness in a range of 2 μm to 4 μm.
8. The method of manufacturing a silicon carbide semiconductor element according to claim 5 , wherein the nickel aluminum film is formed by means of a sputtering method using a nickel aluminum target containing nickel in a range of 40 at % to 60 at %, with the remainder being aluminum.