New experimental evidences of the plasma charging enhanced hot carrier effect and its impact on surface channel CMOS devices

Plasma etching of polysilicon gate in CMOS devices induces plasma edge damage. This damage will be enhanced in the successive plasma processes. New experimental evidences of this effect is examined in this study. Results have been verified for both surface channel n- and p-MOSFETs. First, from the measurements of high-density antenna structures, this enhanced edge damage has been characterized by the charge-pumping profiling technique. Then, a 4-phase edge damage mechanism has been proposed. For the first time, it was found that a two-peak spatial distribution of the interface state was found near the device drain region. We call it Plasma Charging Enhanced Hot Carrier (PCE-HC) effect. This enhanced damage effect will induce further device degradation, in particular for the scaled devices.