3 MECHANISMS DETERMINING SHORT-CHANNEL EFFECTS IN FULLY-DEPLETED SOI MOSFETS

Mechanisms determining short-channel effects (SCE) in fully-depleted ( FD) SOI MOSFET's are clarified based on experimental results of thresh old voltage (V-T) dependence upon gate length, and analysis using a tw o-dimensional (2-D) device simulator. Drain-induced barrier lowering ( DIBL) effect is a well known mechanism which determines the SCE in con ventional bulk MOSFET's. In FD MOSFET's, tno more peculiar and importa nt mechanisms are found out, i.e., the accumulation of majority carrie rs in the body region generated by impact ionization, and the DIBL eff ect on the barrier height for majority carriers at the edge of the sou rce near the bottom of the body. Due to these peculiar mechanisms, V-T dependence upon gate length in the short-channel region is weakened. It is also shown that floating body effects, the scatter of V-T, and t ransient phenomena are suppressed due to the SCE peculiar to FD MOSFET 's.