Comprehensive Study on Trap-induced Bias Instability via High-Pressure D2 and N2 Annealing

Abstract

Forming gas annealing (FGA) in a deuterium (D2) ambient is crucial importance to MOSFET fabrication technologies related to alleviation of trap state at Si/SiO2 interface as well as oxide bulk by D2 passivation. In this study, post-metal annealing (PMA) process with D2 and N2 gases under a high-pressure condition was conducted to verify performance enhancement in gate-enclosed FETs. We explored the trap behaviors inside the bandgap of Si and SiO2 by quantitatively using capacitance-voltage (C-V) characteristics. Furthermore, the change of deuterium and nitrogen ions in Si/SiO2 gate stack before and after the PMA process was directly investigated by time-of-flight secondary ion mass spectroscopy (ToF-SIMS) depthprofiling technique. IEEE