Low-temperature deuterium annealing to improve performance and reliability in a MOSFET

Abstract

Low-temperature deuterium (D2) annealing (LTDA) is applied to improve performances and reliability of a MOSFET. The LTDA is performed at 300 °C, which is at least 100 °C lower than the widely used temperature of forming gas annealing (FGA) with H2, which contributes to reducing a thermal budget especially in the backend-of-the-line (BEOL). DC performances, such as subthreshold slope (SS), threshold voltage (VTH), and on-current (ION) were statistically compared in cases with and without the LTDA to evaluate their improvements. Profiling of D2 by secondary ion mass spectrometry (SIMS) supports that D2 can permeate a gate oxide and passivate dangling bonds and traps near the interface of the SiO2-Si channel. Therefore ION, SS, and VTH were improved, gate leakage current (IG) was reduced, and immunity to positive bias stress (PBS) became better.