Semiconductor device, method of manufacturing same, and sensor

A method of manufacturing a semiconductor device, the method comprising:

• (a) a step of preparing a semiconductor substrate of a first conductivity type containing silicon carbide;
• (b) a step of forming a semiconductor layer of the first conductivity type on the semiconductor substrate by an epitaxial growth method;
• (c) a step of forming a diffusion layer of a second conductivity type different from the first conductivity type, and a first source region of the first conductivity type, a first drain region of the first conductivity type and a first contact layer of the second conductivity type, which are disposed on an upper surface of the diffusion layer, in a first region on an upper surface of the semiconductor layer, and forming a second source region of the second conductivity type, a second drain region of the second conductivity type, and a second contact layer of the first conductivity type in a second region of the upper surface of the semiconductor layer;
• (d) a step of forming a first gate electrode on the semiconductor layer between the first source region and the first drain region via a first insulating film, and forming a second gate electrode on the semiconductor layer between the second source region and the second drain region via a second insulating film;
• and
• (e) after the step (d), a step of forming a first electrode connected to the first contact layer on the semiconductor layer, and forming a second electrode connected to the second contact layer on the semiconductor layer, wherein
• the diffusion layer, the first source region, the first drain region, the first contact layer, the first gate electrode, and the first electrode constitute a first MOSFET,
• the second source region, the second drain region, the second contact layer, the second gate electrode, and the second electrode constitute a second MOSFET,
• the first MOSFET and the second MOSFET constitute a CMOSFET, and
• a first distance from the diffusion layer to the semiconductor substrate is larger than a thickness of a depletion layer extending from the diffusion layer to the semiconductor substrate in response to a potential difference between a first voltage applied to the second source region and a second voltage applied to the first source region in the direction perpendicular to a main surface of the semiconductor substrate.