Semiconductor device having a floating node that can maintain a predetermined potential for long time, a semiconductor memory device having high data maintenance performance, and a method of manufacturing thereof

摘要

In a dynamic random access memory device including an SOI substrate and a field shield isolation region, a p type impurity region is formed between an n type source/drain region of a transistor coupled to a storage node in a dynamic memory cell and an n type impurity region below a field shield electrode. A reverse bias voltage is supplied respectively between the p and n type impurity regions, and between the n type source/drain region of the transistor and the p type body region. As a result, leakage current from the n type source/drain region to the p type body region is compensated for by the leakage current from the n type impurity region to the p type impurity region.