Abstract: A semiconductor device 101 in a bi-directional switch includes: a first electrode 109A, a second electrode 109B, a first gate electrode 112A, and a second gate electrode 112B. In a transition period: when the potential of the first electrode 109A is higher than the potential of the second electrode 109B, a voltage lower than the first threshold voltage is applied to the first gate electrode 112A and a voltage higher than the second threshold value voltage is applied to the second gate electrode 112B; and otherwise, a voltage higher than the first threshold value voltage is applied to the first gate electrode, and a voltage lower than the second threshold value voltage is applied to the second gate electrode.

Abstract: A semiconductor device according to the present invention is a semiconductor device which includes: a semiconductor element; a gate drive circuit; and a connection terminal unit, wherein the semiconductor element includes: a gate electrode pad; and first and second ohmic electrode pads, the connection terminal includes: a first ohmic electrode terminal connected to the first ohmic electrode pad; a second ohmic electrode terminal connected to the second ohmic electrode pad; a gate drive terminal connected to the first ohmic electrode pad; and a gate terminal connected to the gate electrode pad, an input terminal of the gate drive circuit is connected to the gate drive terminal, an output terminal of the gate drive circuit is connected to the gate terminal, and a potential of the first ohmic electrode pad corresponds to a reference potential of the gate drive circuit.

Abstract: A field effect transistor includes a semiconductor stack formed on a substrate, and having a first nitride semiconductor layer and a second nitride semiconductor layer. A source electrode and a drain electrode are formed on the semiconductor stack so as to be separated from each other. A gate electrode is formed between the source electrode and the drain electrode so as to be separated from the source electrode and the drain electrode. A hole injection portion is formed near the drain electrode. The hole injection portion has a p-type third nitride semiconductor layer, and a hole injection electrode formed on the third nitride semiconductor layer. The hole injection electrode and the drain electrode have substantially the same potential.

Abstract: A two-wire AC switch suppressing heat from a bidirectional switch element inside the switch is provided. The two-wire AC switch 100a connected between an AC power supply 101 and a load 102 includes: a bidirectional switch element 103 which flows passing current bi-directionally, selects whether to flow or block the current, is connected in series with the AC power supply 101 and the load 102 to form a closed-loop circuit, and is made of a group-III nitride semiconductor; a full-wave rectifier 104 performing full-wave rectification on power supplied from the AC power supply 101; a power supply circuit 105 smoothing a voltage after the full-wave rectification to generate DC power; a first gate drive circuit 107 and a second gate drive circuit 108 each outputting a control signal to the bidirectional switch element 103; and a control circuit 106 controlling the first and second gate drive circuits 107 and 108.

Abstract: A semiconductor device includes a first transistor formed on a first element region, and a first protecting element including a second transistor formed on a second element region. A second protecting element ohmic electrode is connected to a first gate electrode, a first protecting element ohmic electrode is connected to a first ohmic electrode, and a first protecting element gate electrode is connected to at least one of the first protecting element ohmic electrode and the second protecting element ohmic electrode. The second element region is smaller in area than the first element region.