FLOATING BODY EFFECTS IN POLYSILICON THIN-FILM TRANSISTORS

Floating body effects in polycrystalline silicon thin-film transistors (poly-TFT's) are investigated by means of numerical simulations, The current increase in the output characteristics at large V-DS, usually referred to as ''kink effect,'' is explained by impact ionization occu rring in the high-field region at the drain end of the channel, Its ef fect is enhanced by the action of a parasitic bipolar transistor in th e back-channel region, whose base current arises from the impact gener ated holes. The dependence of the kink on the recombination kinetics i s also investigated.