Diode

A diode comprising:

• a semiconductor substrate having a first main surface and a second main surface opposed to said first main surface;
• a first semiconductor region of a first conductivity type which faces said first main surface and is formed in said semiconductor substrate;
• a second semiconductor region of a second conductivity type which faces said second main surface and is formed in said semiconductor substrate adjacently to said first semiconductor region;
• at least one third semiconductor region of said first conductivity type which faces said second main surface and is formed in said second semiconductor region;
• a first electrode formed on said first main surface;
• and
• a second electrode formed on said second main surface,
• wherein said second electrode being in contact with said second semiconductor region and said third semiconductor region,
• a distance from a boundary of the first and second semiconductor regions to the third semiconductor region is larger than a distance from the boundary to the first main surface, and
• a diameter of a portion of said third semiconductor region which faces said second main surface is approximately 400 μm or less.

A diode comprising:

• a semiconductor substrate having a first main surface and a second main surface opposed to said first main surface;
• a first semiconductor region of a first conductivity type which faces said first main surface and is formed in said semiconductor substrate;
• a second semiconductor region of a second conductivity type which faces said second main surface and is formed in said semiconductor substrate adjacently to said first semiconductor region;
• at least one third semiconductor region of said first conductivity type which faces said second main surface and is formed in said second semiconductor region;
• a first electrode formed on said first main surface;
• and
• a second electrode formed on said second main surface,
• wherein said second electrode being in contact with said second semiconductor region and said third semiconductor region,
• a distance from a boundary of the first and second semiconductor regions to the third semiconductor region is larger than a distance from the boundary to the first main surface, and
• a total area of a portion of said third semiconductor region which faces said second main surface is approximately ⅖ or less of an area of said second main surface.