Semiconductor device 101 includes semiconductor substrate 10, drift layer 20, first electrode 50, and second electrode 60. Semiconductor substrate 10 is of a first conductivity type and is formed of a silicon carbide semiconductor, a gallium nitride semiconductor, or the like. For example, semiconductor substrate 10 is an n-type silicon carbide semiconductor substrate. Drift layer 20 is an epitaxial semiconductor layer of the first conductivity type which is formed on upper surface 10a of semiconductor substrate 10 by epitaxial growth. Drift layer 20 is formed of for example, an n-type silicon carbide semiconductor. Drift layer 20 has a thickness of t. For example, the thickness t is between about 5 μm and about 100 μm (inclusive).