Semiconductor device

A semiconductor device, including:

• a protection device;
• and
• a protected device, the protection device comprising:
• a first semiconductor region of a second conductivity type formed over a substrate;
• a second semiconductor region of the second conductivity type provided in the first semiconductor region, having a higher impurity concentration than the first semiconductor region;
• a third semiconductor region of the second conductivity type formed in a surface layer of the second semiconductor region, having a higher impurity concentration than the second semiconductor region;
• a fourth semiconductor region of the second conductivity type formed in the first semiconductor region and located away from the third semiconductor region, having a higher impurity concentration than the first semiconductor region;
• a fifth semiconductor region of a first conductivity type formed in the first semiconductor region and electrically short-circuited with the fourth semiconductor region;
• a sixth semiconductor region of the first conductivity type located so as to contain the fourth semiconductor region and the fifth semiconductor region;
• a seventh semiconductor region of the first conductivity type formed in the first semiconductor region, located between the second semiconductor region and the sixth semiconductor region away from the sixth semiconductor region, and electrically short-circuited with the third semiconductor region;
• and
• an eighth semiconductor region of the second conductivity type formed in the first semiconductor region and located between the sixth semiconductor region and the seventh semiconductor region away from the seventh semiconductor region, the eighth semiconductor region having a higher impurity concentration than the first semiconductor region.