OBSERVATION OF CHANNEL SHORTENING IN N-METAL-OXIDE-SEMICONDUCTOR FIELD-EFFECT TRANSISTORS ARISING FROM INTERCONNECT PLASMA PROCESSING

Very recently we have demonstrated the possible role of an interconnec t layout in the degradation of n-metal-oxide-semiconductor field-effec t transistors (MOSFETs) during interconnect plasma processing. It was suggested that this role is that of shaping the potential differences between the n-MOSFET's terminals in such a way as to electrically stre ss the device. In this study, we further investigate this degradation and examine its effect on hot carrier reliability. Shifts in g(m) and V-th after a brief hot carrier stress have shown the weak stress resis tance of the n-MOSFETs. After additional charge pumping and transcondu ctance measurements, it is suggested that this weak resistance is due to a channel shortening effect in as-processed devices induced by a po sitive oxide-trapped charge overlapping the drain edge of the channel. Therefore, even a slight change in the magnitude of the charge by eit her electron or hole injection at that edge ultimately leads to changi ng the effective channel length and, hence, most of the de parameters of the n-MOSFETs. (C) 1998 American Vacuum Society.