Semiconductor device with overvoltage protective function

A semiconductor device, with overvoltage protective function, comprising:

• a first semiconductor layer of a first conductivity type;
• a second semiconductor layer of a second conductivity type formed on said first semiconductor layer;
• a third semiconductor layer of the first conductivity type formed on said second semiconductor layer;
• a fourth semiconductor layer of the second conductivity type formed on a first area of said third semiconductor layer;
• an electrode film formed on a second area of said third semiconductor layer;
• and
• a high-density crystal defect layer only in an area in which a depletion layer is formed when a specified reverse voltage is applied to a PN junction between said second and third semiconductor layers, at a position under said electrode film and in which a main current is not disturbed.

A semiconductor device with overvoltage protective function, comprising:

• a first semiconductor layer of a first conductivity type;
• a second semiconductor layer of a second conductivity type formed on said first semiconductor layer;
• a third semiconductor layer of the first conductivity type formed on a first area of said second semiconductor layer;
• and
• a high-density crystal defect layer formed only in an area which a depletion layer is formed when a specified reverse voltage is applied to a PN junction between said first and second semiconductor layers, wherein
• said third semiconductor layer is not formed above said high density crystal defect layer.