Analytic Model of Threshold Voltage Variation Induced by Plasma Charging Damage in High-k Metal–Oxide–Semiconductor Field-Effect Transistor

We discuss plasma charging damage (PCD) to high-k gate dielectrics and the resultant threshold voltage shift (ΔV_th) in n-channel metal–oxide–semiconductor field-effect transistors (n-ch MOSFETs). The PCD induced by the antenna effect is focused on, and ΔV_th and its variation are estimated for MOSFETs treated by various plasma processes. We propose a ΔV_th variation model based on both the power-law dependence of ΔV_th on the antenna ratio r (= exposed metal interconnect area/gate area) and the r distribution deduced from an interconnect-length distribution function (ILDF) in a large-scale integrated (LSI) circuit. Then, we simulate the variations in ΔV_th [σ(ΔV_th)] and the subthreshold leakage current I_off [σ(I_off)], in accordance with the employed r distribution. The model prediction quantitatively shows the effects of PCD on σ(ΔV_th) and σ(I_off): The antenna effect is found to increase σ(ΔV_th) and σ(I_off).