14nm FinFET

The pad oxide grown in the preceding step acts as a critical strain and stress buffer layer to prevent mechanical defects (such as cracks, dislocations, or stacking faults) from propagating into the underlying silicon substrate due to the high intrinsic tensile stress of the silicon nitride film [P1][P2][P5]. The pad nitride deposited in this step serves multiple critical integration functions within the 14nm FinFET patterning flow [P2][T2](Engineering Practice). First, it acts as a robust har…

• [High] Stress-Induced Dislocation Formation and Junction Leakage: The high intrinsic tensile stress of stoichiometric LPCVD silicon nitride films can generate immense mechanical stress concentrated at the active edge interfaces [P1][P4]. If the pad oxide buffer is too thin, or if the thermal budget is poorly controlled, this stress induces silicon dislocation propagation along the <111> slip planes [P1]. When these crystalline defects intersect the junction depletion regions of the 14nm Fi…