Semiconductor device
Reliability of a semiconductor device is improved by suppressing reverse voltage deterioration at the time of reverse bias junction barrier Schottky diode using a substrate containing SiC. In a JBS diode having an active area of 0.1 cm 2 or more, an area of a Schottky interface at which a drift layer and a Schottky electrode are contacted can be sufficiently reduced by relatively increasing a ratio of p-type semiconductor region being a junction barrier region in an active region, and thereby deterioration in reverse voltage caused by defects existing in the drift layer is prevented.
1. A semiconductor device comprising a Schottky barrier diode, the Schottky barrier diode comprising:
a semiconductor substrate having a first conduction type and containing silicon carbide;
a first semiconductor region formed on the semiconductor substrate and having the first conduction type;
an active region having an area of 0.1 cm 2 or more in the main surface of the first semiconductor region;
a plurality of second semiconductor regions formed on the upper surface of the first semiconductor region in the active region and having a second conduction type opposite to the first conduction type;
a first electrode connected by Schottky connection to the first semiconductor region in the active region; and
a second electrode electrically connected to a back surface of the semiconductor substrate,
wherein a multiplication of a density of defects D EP which the first semiconductor region has and an area of the first semiconductor region A S exposed from the second semiconductor regions in the active region satisfies D EP ×A S ≦223.
2. The semiconductor device according to claim 1 ,
wherein the second semiconductor region, is wider than the first semiconductor region.
3. The semiconductor device according to claim 2 ,
wherein the density of defects D EP satisfies D EP >40.4.
4. The semiconductor device according to claim 1 ,
wherein the multiplication of the density D EP and the area A S satisfies D EP ×A S ≦105.
5. The semiconductor device according to claim 1 ,
wherein a third semiconductor region having the first conduction type is formed on the upper surface of the first semiconductor region, and
the third semiconductor region has a higher impurity concentration than that of the first semiconductor region.
6. The semiconductor device according to claim 5 ,
wherein the second semiconductor regions are formed inside of the third semiconductor region.
7. The semiconductor device according to claim 5 ,
wherein the third semiconductor region is formed only in the active region.
8. The semiconductor device according to claim 5 ,
wherein the third semiconductor region has a shallower junction depth than that of the second semiconductor region.
9. The semiconductor device according to claim 1 ,
wherein, in planar view,
each of the first semiconductor region and the second semiconductor region in the active region extends in a first direction along the main surface of the semiconductor substrate;
the first semiconductor region and the second semiconductor region are plurally formed side by side in a second direction; and
the first semiconductor region and the second semiconductor regions are alternately arranged side by side in a second direction.
10. The semiconductor device according to claim 1 ,
wherein a fourth semiconductor region having the second conduction type is formed on the upper surface of the first semiconductor region so as to surround the active region; and
the fourth semiconductor region defines the active region.