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

Low-temperature deuterium (D-2) annealing (LTDA) is applied to improve performances and reliability of a MOSFET. The LTDA is performed at 300 degrees C, which is at least 100 degrees C lower than the widely used temperature of forming gas annealing (FGA) with H-2, which contributes to reducing a thermal budget especially in the backend-of-the-line (BEOL). DC performances, such as subthreshold slope (SS), threshold voltage (V-TH), and on-current (I-ON) were statistically compared in cases with and without the LTDA to evaluate their improvements. Profiling of D-2 by secondary ion mass spectrometry (SIMS) supports that D-2 can permeate a gate oxide and passivate dangling bonds and traps near the interface of the SiO2-Si channel. Therefore I-ON, SS, and V-TH were improved, gate leakage current (I-G) was reduced, and immunity to positive bias stress (PBS) became better.