Semiconductor device
The semiconductor device includes: a semiconductor layer in which a trench is formed having a side surface and a bottom surface; a second conductivity-type layer formed on the semiconductor layer on the side surface and the bottom surface of the trench; a first conductivity-type layer formed on the semiconductor layer so as to contact the second conductivity-type layer; a first electrode electrically connected to the first conductivity-type layer; a second electrode embedded in the trench and electrically connected to the second conductivity-type layer; and a barrier-forming layer which is arranged between the second electrode and the side surface of the trench and which, between said barrier-forming layer and the second conductivity-type layer, forms a potential barrier higher than the potential barrier between the second conductivity-type layer and the second electrode.
1. A semiconductor device comprising:
a semiconductor layer in which a trench having a side surface and a bottom surface is formed;
a second conductivity type layer formed in the semiconductor layer on the side surface and the bottom surface of the trench;
a first conductivity type layer formed in the semiconductor layer so as to be contiguous to the second conductivity type layer;
a first electrode electrically connected to the first conductivity type layer;
a second electrode that is embedded in the trench and that is electrically connected to the second conductivity type layer; and
a barrier-forming layer that is disposed between the side surface of the trench and the second electrode and that forms a potential barrier between the barrier-forming layer and the second conductivity type layer higher than a potential barrier between the second conductivity type layer and the second electrode.
2. The semiconductor device according to claim 1 , wherein the barrier-forming layer is further disposed on an edge portion of the bottom surface of the trench.
3. The semiconductor device according to claim 1 , wherein the barrier-forming layer includes a metal layer made of any one of tungsten (W), platinum (Pt), nickel (Ni), cobalt (Co), and molybdenum (Mo).
4. The semiconductor device according to claim 1 , wherein the barrier-forming layer includes a first conductivity type polysilicon layer.
5. The semiconductor device according to claim 1 , wherein the barrier-forming layer includes an insulating layer made of any one of non-doped polysilicon, silicon oxide (SiO 2 ), aluminum oxide (Al 2 O 3 ), and aluminum oxynitride (AlON).
6. A semiconductor device comprising:
a semiconductor layer in which a taper trench having a side surface and a bottom surface is formed, the side surface being inclined with respect to the bottom surface at an obtuse angle;
a second conductivity type layer formed in the semiconductor layer on the side surface and the bottom surface of the taper trench, the second conductivity type layer becoming thicker in a lateral direction along a surface of the semiconductor layer from the side surface corresponding to an inclination of the side surface of the taper trench;
a first conductivity type layer formed in the semiconductor layer so as to be contiguous to the second conductivity type layer;
a first electrode electrically connected to the first conductivity type layer;
a second electrode that is embedded in the taper trench and that is electrically connected to the second conductivity type layer; and
a barrier-forming layer disposed between the side surface of the taper trench and the second electrode and forming a potential barrier between the barrier-forming layer and the second conductivity type layer higher than a potential barrier between the second conductivity type layer and the second electrode.
7. The semiconductor device according to claim 6 , wherein the barrier-forming layer is further disposed on an edge portion of the bottom surface of the taper trench.
8. The semiconductor device according to claim 6 , wherein the barrier-forming layer includes a metal layer made of any one of tungsten (W), platinum (Pt), nickel (Ni), cobalt (Co), and molybdenum (Mo).
9. The semiconductor device according to claim 6 , wherein the barrier-forming layer includes a first conductivity type polysilicon layer.
10. The semiconductor device according to claim 6 , wherein the barrier-forming layer includes an insulating layer made of any one of non-doped polysilicon, silicon oxide (SiO 2 ), aluminum oxide (Al 2 O 3 ), and aluminum oxynitride (AlON).