RASP: Reliability ab initio simulation package of MOSFETs based on all-state model

TL;DR

RASP is a comprehensive simulation tool that models all defect configurations in MOSFET gate dielectrics to accurately predict reliability degradation, especially under defect-induced conditions.

Contribution

It introduces the all-state model for MOSFET reliability simulation, considering all defect configurations and transition pathways, improving accuracy over traditional models.

Findings

Oxygen vacancies significantly contribute to NBTI.

RASP accurately predicts threshold voltage shifts.

All-state model enhances reliability simulation precision.

Abstract

As transistors continue to scale down, device reliability has become a critical concern. In order to accurately simulate defect-induced reliability degradation in MOSFET based logic, memory and power devices, we develop RASP (Reliability Ab initio Simulation Package), which implements the all-state model for reliability simulation. Unlike conventional two-state and four-state models that consider only two and four defect configurations respectively, the all-state model systematically considers all possible defect configurations in amorphous gate dielectrics and all nonradiative multiphonon (NMP) and thermal transition pathways among them. With defect parameters obtained from ab initio calculations as input, RASP enables accurate simulation of threshold voltage shifts caused by defects. Using RASP to simulate oxygen vacancies in a-SiO$_2$, we find that they are a non-negligible source of negative bias temperature instability (NBTI).