Investigation of different NBTI simulation models

• Main Author: Low, Elaine Xiao Mei.
• Other Authors: Ang Diing Shenp
• Format: Final Year Project
• Language: English
• Published: 2012
• Subjects: DRNTU::Engineering::Electrical and electronic engineering::Microelectronics
• Online Access: http://hdl.handle.net/10356/50346
• Institution: Nanyang Technological University

Negative Bias Temperature Instability (NBTI) is an important reliability concern since integrated circuit technology has entered the ultra-scaled CMOS technology node. This phenomenon arises from traps generation at the dielectric-substrate interface under the presence of electric field and high temperature, resulting severe shift in the key electrical parameters of device. Dynamic NBTI stress is the main concern in the state-of-the-art technology due to the switching in logic devices that serves as the basic unit of all IC's. Several models have been proposed to interpret the degradation and recover phenomena of PMOSFET under dynamic NBTI but the constant recovery after many dynamic stress cycles is yet to be clarified. In this project, dynamic NBTI was simulated with two different models: reaction-diffusion (R-D) model and two stage model. R-D model shows emphasis on interface trap generation and hydrogen transport whilst two stage model accounts hole trapping and its coupling with interface trap to the degradation mechanism. Simulation result of both models presented in this project shows a decreasing recovery with cycles which do not conform with the experiment result that produces steady recovery. It is also found that contradiction occurs at the prediction by hydrogen diffusion in R-D model and the coupling of hole trapping and interface traps in two stage model. We proposed that a certain structure relaxation should be considered into the hole trapping model and the hole trapping mechanism should be independent with the mechanism of interface traps generation.