Experimental comparison of programming mechanisms in 1T-DRAM cells with variable channel length

The bulk DRAM scaling requirements have lead to many different concepts of capacitor-less single-transistor (1T) DRAM. Amongst the various effects used to program the cell, this study is focused on the Impact Ionization (II), the most common mechanism to store charges in the body of the cell, and the Meta-Stable Dip (MSD) effect. Dynamic measurements are presented showing the impact of the gate length reduction on both the II and the MSD programming mechanisms. It is found that MSD is less impacted by the scaling of standard SOI MOSFETs without specific optimization. Those attractive performances result from the dynamic coupling between the front and back gates in Fully Depleted SOI (FDSOI) transistors.