Manufacturing method for semiconductor device, and semiconductor device

Abstract

To provide a manufacturing method for a semiconductor device, in which the amount of defects in a gate insulating layer is reduced.SOLUTION: A manufacturing method for a semiconductor device in an embodiment includes: forming a trench in a silicon carbide layer whose surface is inclined by 0 degrees or more and 8 degrees or less to {0001} plane; forming a silicon oxide film whose atomic concentration of oxygen (O) is less than 200% of the atomic concentration of silicon (Si) on an inner surface of the trench; performing a first thermal process in an atmosphere containing a nitrogen oxide gas after forming the silicon oxide film; performing a second thermal process in an atmosphere containing at least one element selected from the group consisting of hydrogen (H), deuterium (D), and fluorine (F) after the first thermal process; and forming a gate electrode on the silicon oxide film after the second thermal process.SELECTED DRAWING: Figure 4