Diode and semiconductor device including built-in diode

1. A diode comprising:

a cathode electrode;

a cathode region made of a first conductivity type semiconductor;

a drift region made of the first conductivity type semiconductor;

an anode region made of a second conductivity type semiconductor;

an anode electrode made of metal;

a barrier region formed between the drift region and the anode region, and made of the first conductivity type semiconductor having a concentration higher than that of the drift region;

a pillar region formed so as to extend between the barrier region and the anode electrode and contact the barrier region, and made of the first conductivity type semiconductor; and

a barrier height adjusting region formed so as to be located between the pillar region and the anode electrode, and contact the pillar region and the anode electrode, wherein

the barrier height adjusting region includes at least one component selected from the group consisting of the second conductivity type semiconductor having a concentration lower than that of the anode region, the first conductivity type semiconductor having a concentration lower than that of the pillar region, and an i-type semiconductor,

the barrier height adjusting region and the anode electrode are connected through a Schottky junction, and

a concentration of the pillar region is higher than a concentration of the barrier region.

2. The diode according to claim 1 , further comprising an electric field progress preventing region formed between the barrier region and the drift region and made of the second conductivity type semiconductor.

3. The diode according to claim 1 , wherein a trench extending from the anode region to the drift region is formed, and

a trench electrode which is coated with an insulating film is formed inside the trench.

4. The diode according to claim 1 , further comprising a cathode short-circuit region partially formed in the cathode region and made of the second conductivity type semiconductor.

5. A semiconductor device comprising the diode according to claim 1 and an insulated-gate bipolar transistor (IGBT) that are integrally formed,

wherein the IGBT includes:

a collector electrode;

a collector region made of the second conductivity type semiconductor;

a second drift region continuously formed from the drift region and made of the first conductivity type semiconductor;

a body region made of the second conductivity type semiconductor;

an emitter region made of the first conductivity type semiconductor;

an emitter electrode made of metal;

a gate electrode opposite to the body region between the emitter region and the second drift region via an insulating film;

a second barrier region formed between the second drift region and the body region, and made of the first conductivity type semiconductor having a concentration higher than that of the second drift region;

a second pillar region formed so as to extend between the second barrier region and the emitter electrode and contact the second barrier region, and made of the first conductivity type semiconductor; and

a second barrier height adjusting region formed so as to be located between the second pillar region and the emitter electrode, and contact the second pillar region and the emitter electrode,

wherein

the second barrier height adjusting region includes at least one component selected from the group consisting of the second conductivity type semiconductor having a concentration lower than that of the body region, the first conductivity type semiconductor having a concentration lower than that of the second pillar region, and an i-type semiconductor, and

the second barrier height adjusting region and the emitter electrode are connected through a Schottky junction.

6. The semiconductor device according to claim 5 , further comprising a second electric field progress preventing region formed between the second barrier region and the second drift region and made of the second conductivity type semiconductor.