Significant Lifetime Improvement of Negative Bias Thermal Instability by Plasma Enhanced Atomic Layer Deposition SiN in Stress Memorization Technique

In this work, the significant lifetime improvement of negative bias thermal instability (NBTI) is demonstrated by the introduction of a thin SiN layer fabricated by plasma enhanced atomic layer deposition (PEALD) in stress memorization technique (SMT). The thin SiN film is deposited before the plasma enhanced chemical vapor deposition (PECVD) of SiN layer with a high tensile stress. It is revealed that the possible H2 escape accompanied with interface de-passivation can be effectively suppressed by this thin PEALD SiN layer, which may further reduce the interface states at Si/gate dielectric interface. Hence, about 500% NBTI lifetime improvement for PMOSFETs is demonstrated without obvious performance degradation for both NMOSFETs and PMOSFETs.