In an embodiment, a semiconductor device includes: a main transistor having a load path; a sense transistor configured to sense a main current flowing in the load path of the main transistor; and a bypass diode structure configured to protect the sense transistor and electrically coupled in parallel with the sense transistor. A sense transistor cell of the sense transistor includes a sense trench and a sense mesa. The sense trench and a bypass diode trench of the bypass diode structure form a common trench. The sense mesa and a bypass diode mesa of the bypass diode structure form a common mesa.