Impact of Nitrogen Annealing Concentration on p-Type FinFET Reliability Caused by Edge Effect

This study investigates abnormal degradation behavior in long-channel p-type fin-shaped field-effect transistors (FinFETs) with nitrogen annealing, evaluated through negative bias stress (NBS). A correlation between gate leakage and channel length was observed, showing a similar trend to the threshold voltage shift (Δ<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>th</roman></sub><roman xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">)</roman>. Gate-induced drain leakage (GIDL) analysis further revealed nonuniform passivation between the center and edge regions of the channel. To assess the reliability, hot carrier stress (HCS) was applied under different nitrogen annealing concentrations, and the results were validated using devices with varying channel lengths. Negative bias temperature instability (NBTI) stress was also employed to evaluate the interfacial layer quality, confirming a channel length-dependent degradation mechanism induced by variations in nitrogen annealing concentration. A physical model is proposed to explain the edge effect caused by insufficient nitrogen passivation. The findings indicate that precise control of annealing gas concentration is essential for minimizing performance degradation resulting from channel length variations.