JPS568839A - Semicondcutor device - Google Patents

Abstract

PURPOSE:To detect by itself the degree of deterioration of semiconductor device by a method wherein a structure of rectifying contact of a MIS capacity is prepared in the neighborhood of semiconductor device to be monitored about deterioration locating in the same semiconductor substrante, and an electric charge flowed to a depletion layer belonging to this structure is detected. CONSTITUTION:Regions 21, 22 containing an impurity are formed on a semiconductor substrate, an electrode 3 is prepared putting insulating films between them to form a unit transistor, the region 21 is connected to the earth and a power source 5 is connected to the region 22 and the electrode 3 respectively. To detect the deteriorated condition of this transistor, an impurity region 25 of rectifying contact structure is prepared being added in the same substrate provided with the transistor to form a p-n junction between the transistor, and is connected to the reverse biasing power source 5 through an ammeter 4. When the transistor is made to operates in this constitution, as generated holes flow also into a depletion layer existing under the region 25, that the degree of deterioration of the transistor can be observed by a reverse current through the p-n junction.