[paper] Abstraction NBTI model

Stephan Adolf and Wolfgang Nebel

Abstraction NBTI model

it - Information Technology, Sep. 2021

DOI: 10.1515/itit-2021-0005

Abstract: Negative Bias Temperature Instability (NBTI) is one of the major transistor aging effects, possibly leading to timing failures during run-time of a system. Thus, one is interested in predicting this effect during design time. In this work, an Abstraction NBTI model is introduced reducing the state space of trap-based NBTI models using two abstraction parameters, applying a state transformation to incorporate variable stress conditions. This transformation is faster than traditional approaches. Currently, the conversion into estimated threshold voltage damages is a very time-consuming process.

Fig: Trap in the gate oxide of a PMOS transistor

Acknowledgement: The author thanks Kim Grüttner for proofreading the manuscript of the paper. This research is funded by the German Research Foundation through the Research Training Group “SCARE: System Correctness under Adverse Conditions” (DFG-GRK 1765/2), https://www.uni-oldenburg.de/en/scare/. The simulations were partly performed on the HPC Cluster CARL at the University of Oldenburg (Germany), funded by the DFG through its Major Research Instrumentation Program (INST 184/157-1 FUGG) and the Ministry of

Science and Culture (MWK) of the Lower Saxony State.

[paper] Aged MOSFET and Its Compact Modeling

F. A. Herrera, M. Miura-Mattausch, T. Iizuka, H. Kikuchihara, H. J. Mattausch and H. Takatsuka, Universal Feature of Trap-Density Increase in Aged MOSFET and Its Compact Modeling

SISPAD, Kobe, Japan, 2020, pp. 109-112

DOI: 10.23919/SISPAD49475.2020.9241674

Abstract: Our investigation focuses on accurate circuit aging prediction for bulk MOSFETs. A self-consistent aging modeling is proposed, which considers the trap-density Ntrap increase as the aging origin. This Ntrap is considered in the Poisson equation together with other charges induced within MOSFET. It is demonstrated that a universal relationship of the Ntrap increase as a function of integrated substrate current, caused by device stress, can describe the MOSFET aging in a simple way for any device-operating conditions. An exponential increase with constant and unitary slope of the Ntrap is found to successfully predict the aging phenomena, reaching a saturation for high stress degradation. The model universality is verified additionally for any device size. Comparison with existing conventional aging modeling for circuit simulation is discussed for demonstrating the simplifications due to the developed modeling approach

Fig: Schematic of the density-of-state (DOS) model as a function of the state-energy difference from the conduction-band edge, with two parameters gc and Es introduced as new model features.