| 摘要 |
PURPOSE:To prevent the generation of the defective operation of a latch-up, etc. by turning a parasitic transistor ON by applying the potential of an N-type semiconductor substrate into a semiconductor memory circuit device up to maximum potential applied at that time by a semiconductor switch. CONSTITUTION:When the writing or erasing of a MNOS element 6 is not conducted, an N-type semiconductor substrate 1 is connected to VDD through a diode 20, thus clamping the potential of the N-type semi-conductor substrate 1 at VDD. Consequently, since a parasitic transistor 12 is reversely biassed, parasitic thyristors by parasitic transistors 11 and 12 are not turned ON even by any disturbance. When high voltage is applied to a P-type semiconductor region 2 in order to erase the MNOS element 6, high voltage is applied to the N-type semiconductor substrate 1 through an N<+> diffusion 8. The diode 20 is reversely biassed at that time, and power supplies are not short-circuited. High voltage is applied to the P-type semiconductor region 2 as a substrate for the MNOS element 6 through a P<+> diffusion 7. |
