SEMICONDUCTOR DEVICE AND FABRICATING METHOD THEREOF

摘要

PURPOSE: A semiconductor device is provided to miniaturize a semiconductor circuit, by improving a refresh characteristic in a memory cell region even if a semiconductor integrated circuit is miniaturized and by forming a shallow well in a logic circuit region. CONSTITUTION: A semiconductor layer(1) is of the first conductivity type. The first impurity region(31) of the second conductivity type is formed on the main surface of the semiconductor layer, including the first impurity density peak. The second impurity region(43) of the first conductivity type is disposed on the main surface of the semiconductor layer having the first impurity region, surrounding all of the first impurity region and including the second impurity density peak in a portion shallower than the first impurity density peak. The third impurity region of the first conductivity type surrounds the second impurity region in a region inserted into the first and second impurity regions of the main surface of the semiconductor layer, including the third impurity density peak in a portion shallower than the second impurity density peak. The first field effect device of the second conductivity type is formed on the main surface of the second impurity region.