Trench-gated MOSFET including schottky diode therein

1. A trench MOSFET, comprising:

a gate electrode having a trench gate structure;

a gate insulating film formed to surround the gate electrode;

an n-type diffusion layer formed to face the gate electrode via the gate insulating film at an upper portion of the trench;

a p-type base layer formed to face the gate electrode via the gate insulating film at a lower portion than the upper portion of the trench;

an n-type epitaxial layer locating to face the gate electrode via the gate insulating film at a further lower portion than the lower portion of the trench;

a metal layer formed departing from the trench in parallel with a depth direction of the trench, the metal layer penetrating the n-type diffusion layer and the p-type base layer to reach the n-type epitaxial layer; and

a p-type layer with higher impurity concentration than the p-type base layer, locating to be in contact with the p-type base layer and the metal layer.

2. A trench MOSFET as set forth in claim 1 ,

wherein a depth of the metal layer is shallower than a depth of the trench.

3. A trench MOSFET as set forth in claim 1 ,

wherein a depth of the metal layer is shallower than a depth of a deepest portion of the p-type base layer.

4. A trench MOSFET as set forth in claim 1 ,

wherein a depth of a deepest portion of the p-type base layer is deeper than depths of the trench and the metal layer.

5. A trench MOSFET as set forth in claim 1 ,

wherein side surfaces of the metal layer in a depth direction is not in contact with the n-type epitaxial layer.

6. A trench MOSFET as set forth in claim 1 , further comprising:

an n-type layer with higher impurity concentration than the n-type diffusion layer, locating between the n-type diffusion layer and the metal layer.