Reliability Characteristics of poly Si-gated High Quality Chemical Vapor Deposition Hafnium Oxide Gate Dielectric

Abstract

In this paper, reliability characteristics of chemical vapor deposition (CVD) HfO2 gate stacks with n+-poly-Si gate electrode are investigated systematically, along with long-term lifetime projection. The area dependence and critical defect density of CVD HfO2 gate stacks have been investigated and compared to that of SiO2. Results show that in addition to the significant reduction of tunneling leakage current by a factor of 103–104, a comparable Weibull slope factor and critical defect density are obtained from a high quality CVD HfO2 mainly due to the thicker physical thickness, compare to SiO2. Considering the cumulative impact of temperature acceleration at 150°C, scaling of an effective gate oxide area of 0.1 cm2 and a maximum allowed fraction of failures of 0.01%, the maximum allowed operating voltage is projected to be ∼0.85 V for HfO2/poly-Si gate stack with equivalent oxide thickness (EOT) = 14.5 Å.