Thickness dependence of Weibull slopes of HfO2 gate dielectrics

Breakdown voltage distribution, Weibull slopes, and area scaling factors have been investigated for HfO2 gate dielectrics in order to gain a better understanding of the breakdown mechanism. Weibull slope of thick HfO2 (e.g., beta approximate to 4 for EOT = 2.5 nm) is smaller than that of SiO2 with similar physical thickness, whereas beta of the thinner HfO2 (e.g., beta approximate to 2 for EOT = 1.4 nm) is similar to that Of SiO2. The implication of the thickness dependence of beta is discussed.