Semiconductor device with suppressed two-step on phenomenon
A semiconductor device includes an IGBT region with a bottom-body region on a front surface side of an IGBT drift region, an IGBT barrier region on a front surface side of the bottom-body region, and a top-body region on a front surface side of the IGBT barrier region. A diode region is include with a bottom-anode region on a front surface side of the diode drift region, a diode barrier region on a front surface side of the bottom-anode region, a top-anode region on a front surface side of the diode barrier region, and a pillar region extending from the front surface of the semiconductor substrate, piercing the top-anode region, and reaching the diode barrier region, and connected to the front surface electrode and the diode barrier region. An impurity concentration of the top-body region is lower than an impurity concentration of the bottom-anode region.
1. A semiconductor device comprising:
a semiconductor substrate; and
a front surface electrode configured of metal provided on a front surface of the semiconductor substrate,
wherein
the semiconductor substrate comprises an IGBT (Insulated Gate Bipolar Transistor) region and a diode region,
the IGBT region comprises:
an n-type IGBT drift region;
a p-type bottom-body region provided on a front surface side of the IGBT drift region;
an n-type IGBT barrier region provided on a front surface side of the bottom-body region;
a p-type top-body region provided on a front surface side of the IGBT barrier region;
an n-type emitter region provided on a front surface side of the top-body region; and
a gate trench extending from the front surface of the semiconductor substrate, piercing the emitter region, the top-body region, the IGBT barrier region and the bottom-body region, and reaching the IGBT drift region, and
the diode region comprises:
an n-type diode drift region;
a p-type bottom-anode region provided on a front surface side of the diode drift region;
an n-type diode barrier region provided on a front surface side of the bottom-anode region;
a p-type top-anode region provided on a front surface side of the diode barrier region;
an n-type pillar region extending from the front surface of the semiconductor substrate, piercing the top-anode region, and reaching the diode barrier region, and connected to the front surface electrode and the diode barrier region; and
a gate trench extending from the front surface of the semiconductor substrate, piercing the top-anode region, the diode barrier region and the bottom-anode region, and reaching the diode drift region,
wherein
an average impurity concentration of the top-body region is lower than an average impurity concentration of the bottom-anode region.
2. The semiconductor device according claim 1 , wherein the front surface electrode is configured of titanium.
3. The semiconductor device according claim 1 , wherein a highest impurity concentration of the top-body region is lower than a lowest impurity concentration of the bottom-anode region.