Semiconductor power devices have conventionally become the focus of attention, which are mainly used for systems in various power electronics fields such as motor control systems and power conversion systems.
As semiconductor power devices of this type, SiC semiconductor devices having a trench-gate structure have been proposed, for example.
For example, Patent Literature 1 discloses a field effect transistor including an n+-type SiC substrate, an n−-type epitaxial layer (drift region) formed on the SiC substrate, a p-type body region formed at a surface side of the epitaxial layer, an n+-type source region formed at a surface side within the body region, a grid-shaped gate trench formed in a manner penetrating through the source region and the body region to reach the drift region, a gate insulating film formed on the inner surface of the gate trench, a gate electrode embedded in the gate trench, a source trench formed in a manner penetrating through the source region and the body region to reach the drift region at a position surrounded by the grid-shaped gate trench, and a source electrode formed in a manner entering the source trench