Semiconductor device and power conversion device using same
It is intended to provide a semiconductor device capable to improve a controllability of dv/dt by a gate drive circuit during a turn-on switching period, while maintaining a low loss and a high breakdown voltage. Trench gates are disposed so as to have narrow distance regions and wide distance regions, wherein each of the narrow distance regions is provided with a channel region, and each of the wide distance regions is provided with trenches, each trench having an electrode electrically connected to the emitter electrode. In this manner, even if a floating-p layer is removed, it is possible to reduce a feedback capacity and maintain a breakdown voltage.
1. A semiconductor device comprising:
a first semiconductor layer of a first conductivity type;
a second semiconductor layer of a second conductivity type adjacent to the first semiconductor layer;
a plurality of first trenches;
gate electrodes each of which is provided in each of the plurality of the first trenches; and
a first and a second regions which are disposed between the first trenches and the second region has a wider distance between the first trenches than the first region,
wherein the first region is provided with:
a third semiconductor layer of the first conductivity type adjacent to the second semiconductor layer; and
a fourth semiconductor layer of the second conductivity type adjacent to the third semiconductor layer,
the gate electrode is disposed in the first trench, contacting with the third semiconductor layer, the fourth semiconductor layer and the second semiconductor on each surface thereof via a first insulation film, and provided with:
a first electrode that contacts in a low resistance with the first semiconductor layer; and
a second electrode that contacts in a low resistance with the third semiconductor layer and the fourth semiconductor layer,
the second region is provided with:
a plurality of second trenches; and
a third electrode disposed in each of the plurality of the second trenches, having a second insulation film between itself and a trench sidewall, and electrically connected to the second electrode, and
the second semiconductor layer is interposed between the first trench and the second trench.
2. The semiconductor device, according to claim 1 , further comprising:
a fourth electrode that is disposed below the gate electrode in the first trench, having a third insulation film between itself and a trench sidewall, and electrically connected to the second electrode.
3. The semiconductor device, according to claim 1 ,
wherein
a thickness of the second insulation film is thicker than a thickness of the first insulation film.
4. The semiconductor device, according to claim 2 ,
wherein
thicknesses of the second and third insulation films are thicker than a thickness of the first insulation film.
5. The semiconductor device, according to claim 1 ,
wherein
a distance between the second trench closest to the first trench, and the first trench is equal to or smaller than a distance between the first trenches in the first region.
6. The semiconductor device, according to claim 1 ,
wherein the second region is further provided with
a fifth semiconductor layer, in a floating state, of the second conductivity type, between the second trenches.
7. The semiconductor device, according to claim 6 ,
wherein
a deepness of the fifth semiconductor layer is deeper than a deepness of the second trench.
8. The semiconductor device, according to claim 1 ,
wherein
the gate electrode and the third electrode are made of polysilicon.
9. The semiconductor device, according to claim 2 ,
wherein
the gate electrode and the third electrode, and the fourth electrode are made of polysilicon.
10. The semiconductor device, according to claim 1 ,
wherein
the second semiconductor layer includes
a first portion that is adjacent to the first semiconductor layer, and
a second portion that is adjacent to the first portion, and
a carrier concentration of the first portion is higher than a carrier concentration of the second portion.
11. The semiconductor device, according to claim 1 ,
wherein
the second semiconductor layer includes
a first portion that is adjacent to the third semiconductor layer, and
a second portion that is adjacent to the first portion, and
a carrier concentration of the first portion is higher than a carrier concentration of the second portion.
12. The semiconductor device, according to claim 1 ,
wherein
a fifth semiconductor layer of the second conductivity type is provided in the third semiconductor layer, and
a carrier concentration of the fifth semiconductor layer is higher than a carrier concentration of the second semiconductor layer.
13. A power conversion device comprising:
a pair of DC terminals;
AC terminals, number of which is equal to a number of phases; and
a plurality of semiconductor switching elements which are connected between the DC terminals and the AC terminals,
wherein
each of the plurality of the semiconductor switching elements is the semiconductor device according to claim 1 .