Gate oxide breakdown has been studied in the circuit-like patterns, i.e. e-Fuse arrays and two-stage inverter circuit. It is observed that time-dependent dielectric breakdown (TDDB) lifetime of eFuse chip is larger compared to discrete devices. Gate oxide breakdown study using two-stage inverter circuit (1 st -stage I/O N/PMOS worked as current limiting transistors and 2 nd -stage core N/PMOS is stressed transistors) reveals that, even by applying a significant high voltage stress (≤ 3xVdd) on stressed device, the stress device will suffer only soft breakdown not a hard breakdown and it is independent with the current drive capability of current limiting transistors. Soft breakdown results in very small voltage drop across the current limiting device (i.e. between source and drain terminals), which will have negligible impact on the circuit functionality. It suggests circuit functionality will be immune from gate oxide breakdown in normal circuit operating condition, i.e. V dd of ~1V, and designers will get extra reliability margin. Our HSPICE simulation results on ring oscillator (RO) also suggest the logic circuit functionality immunity with gate oxide breakdown. Keywords -(Breakdown (BD), Hard BD (HBD), Soft BD (SBD), time-depedent dielectric BD (TDDB), e-Fuse, 2-stage inverter circuit, Ring oscillator (RO))
In this paper, frequency dependence of the Positive Bias Temperature Instability (PBTI) and the Time Dependent Dielectric Breakdown (TDDB) at relative high frequency range (1KHz ~ 500MHz) in high-k/metal-gate (HK/MG) NMOS are investigated. An explanation of both dependencies of PBTI and TDDB with capture/emission times is proposed. This paper is divided into three parts: 1) AC PBTI and the existence of critical frequencies is discussed, 2) Frequency dependence of TDDB and its implication of the time to form leakage path, and 3) AC BTI/TDDB impacts on logic circuit, which is studied using simulated frequency degradation of ring oscillators (ROs). Based on the negligible frequency degradation of RO with worst I dsat degradations, we conclude that, for circuits operating in a continuous switching mode, BTI/TDDB will not be an unsurpassable reliability issue.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.