JPS6425558A - Semiconductor memory device and manufacture thereof - Google Patents

Abstract

PURPOSE:To increase the amount of charge accumulation and to prevent soft errors, by constituting a semiconductor region, which is in contact with a drain region and has high impurity concentration having a reverse conductivity type with respect to the drain region, at the lower part of the drain region and a channel forming region of a MISFET, which is an accumulating node of the amount of the charge accumulation that becomes information. CONSTITUTION:One end part of a gate electrode of each driving MISFET Q is directly connected to semiconductor regions 9 and 11 through connecting holes 6A, which are provided in a gate insulating film 6. The semiconductor regions 9 are provided so as to include or wrap the high impurity concentration regions 11, which are used as the drain regions of the driving MISFETs Q. The junction depth is constituted deeply. Thus the turning of the semiconductor region 9 into the lower part of the gate electrode 7 of each driving MISFET Q (to the side of a channel forming region) becomes large. The capacitance of the gate is increased by increasing the area, where the semiconductor regions 9 (drain regions) and the gate electrodes 7 are overlapped. The charge accumulating amount of a capacitor C can be increased. Therefore, when minority carries, to be generated by alpha rays in a well region 2, intrude into the capacitor element C for accumulating the charge, the inversion of information can be made hard to occur.