Suppression of ion-induced charge collection against soft-error

Suppression of charge carrier collection has been investigated to clarify the validity of buried well structures against soft-errors in dynamic random-access memories (DRAMs). The suppression of charge carrier collection of twin wells on a Si wafer and a twin well on epitaxial wafers has been measured for DRAM application. The collection of charge carriers induced by microprobe irradiation could be reduced by a buried layer formed at different Boron dose. The carrier collection efficiency of the diode with a twin well (i.e., retrograde well) with a higher dose can be reduced to 50% that of the diode with a twin well in an epitaxial layer.