Semiconductor device

A semiconductor device comprising a plurality of cells, each of the plurality of cells comprising a single transistor, the single transistor comprising:

• a first semiconductor region of a first conductive type;
• a base region of a second conductive type on the first semiconductor region;
• a source region of the first conductive type on the base region;
• a gate electrode penetrating through the base region in a first direction to reach the first semiconductor region and extending in a second direction;
• and
• a gate insulting film between the gate electrode and the first semiconductor region, between the gate electrode and the base region, and between the gate electrode and the source region,
• wherein the single transistor has a first threshold voltage and a second threshold voltage higher than the first threshold voltage,
• when a gate voltage of the single transistor is lower than the first threshold voltage, channels of the single transistor in both of the region having the first threshold voltage and the region having the second threshold voltage are in an off-state, and
• when the gate voltage becomes higher than the first threshold voltage, a channel in the region having the first threshold voltage turns into an on-state whereas a channel in the region having the second threshold voltage remains in the off-state.