Two Specific Behaviors of Breakdown Occurrence Depending on N2 Annealing Temperature in Poly-Si/SiN/Poly-Si Capacitors

Abstract

A time-dependent dielectric breakdown assessment was performed on a poly-Si/SiN/poly-Si capacitor to investigate the dependence of the breakdown occurrence on the N2 annealing temperature. We identified two specific behaviors of the breakdown occurrence dependent on the N2 annealing temperature: a peak at around 900 °C and a monotonic increase at temperatures above 1000 °C. Electron spin resonance spectroscopy was used to observe defects in the SiN film on the Si substrate, and the two behaviors showed good correlations with two types of changes in the defect densities: Pb centers on the Si substrate at the SiN/Si interface and an unidentified spectrum showing a local maximum at 900 °C; and E′ centers in the SiO2 film at the SiN/Si interface and K centers in the SiN film showing a monotonic increase at higher temperatures. We propose that the two specific behaviors of breakdown occurrence can be attributed to not only bulk defects in the SiN film but also defects near the SiN/Si interface.