Charge pumping SOS-MOS transistor memory

A new memory cell is proposed, utilizing the inherent features of the floating substrate of SOS-MOS transistors. The operations of the fabricated cell are also demonstrated. The potential of the floating substrate is found to be changed by the charge pumping action (WRITE "1"). The injected charge is stored in the substrate due to the reverse-biased junctions at the source and drain (STORE), and is removed by the avalanche multiplication current (WRITE "0"). The conditions to change the threshold voltage by the substrate bias is studied (READ). For the lower impurity concentration in the substrate or the higher substrate bias V
sub
, it is found that threshold voltage is independent of V
sub
.