Patent ID: 8242534
Filing Date: 2012-08-14
Classification: H01L

Abstract:
1. A semiconductor device comprising: a semiconductor substrate of a first conductivity type, having a first major surface and a second major surface lying on the side opposite to the first major surface; a first semiconductor region of a second conductivity type formed on the side of the first major surface of the semiconductor substrate; a second semiconductor region of a second conductivity type formed on the side of the first major surface of the semiconductor substrate to be internally included in the first semiconductor region; third and fourth semiconductor regions of a first conductivity type formed on the side of the first major surface of the semiconductor substrate to be internally included in the second semiconductor region and spaced apart from each other; a fifth semiconductor region of a second conductivity type formed on the side of the second major surface of the semiconductor substrate; a sixth semiconductor region of a first conductivity type formed on the side of the second major surface of the semiconductor substrate to be internally included in the fifth semiconductor region; a first electrode formed over the first major surface of the semiconductor substrate to contact the second and third semiconductor regions; a second electrode formed over the first major surface of the semiconductor substrate to contact the second and fourth semiconductor regions; a third electrode over the second major surface of the semiconductor substrate to contact the fifth and sixth semiconductor regions; and a substrate region of a first conductivity type comprised of part of the semiconductor substrate and interposed between the first semiconductor region and the fifth semiconductor region, wherein a first thyristor is formed between the third electrode and the first electrode by the fifth semiconductor region, the substrate region, the first semiconductor region, the second semiconductor region and the third semiconductor region, wherein a second thyristor is formed between the first electrode and the third electrode by the second semiconductor region, the first semiconductor region, the substrate region, the fifth semiconductor region and the sixth semiconductor region, wherein the first thyristor and the second thyristor are opposite in the direction of currents flowing between the first electrode and the third electrode, and wherein the second semiconductor region is higher than the first semiconductor region in impurity concentration.