| 摘要 |
PURPOSE:To perform evaluation of a soft error in a highly reliable manner by a method wherein ''1'' and ''0'' which are different each other are written in the cell of a memory device in advance, they are read out in the bit line direction under the irradiation of radioactive rays and compared with the written-in information. CONSTITUTION:Memory cells M1, M2... are connected between a bit line B and an inversion B, and ''1'' and ''0'' are written-in alternately, for example. At least information the different from others is to be written in a cell. As ''0'' is recorded with the bit line B in high level and the inverted bit line in high level, the bit line is used by inverting high and low levels when a read-out process is performed. Also, a read-out process is performed while radioactive rays are being projected in order to form the transitional instable state which is approximate to the actual condition, and when the result is different from the written- in information, it is counted as an error. According to this method, a soft error can be measured accurately on the range of practical operation of a semiconductor device in a short period, and a highly reliable evaluation can be obtained by performing a measurement under the most severe conditions. |
