ABSTRACT
This chapter focuses on Bias temperature instability (BTI) and dielectric breakdown–related reliability issues, which solely depend on the gate dielectric stack, while hot carrier injection is strongly modulated by junction profile and design. It discusses the reliability impacts of implementing gate-first and replacement metal gate high-κ/metal gate (HKMG) flows. The optimization of an HKMG gate stack for all flows is fundamentally similar, requiring careful consideration of thermal budgets, underlying substrates, and interface treatments. For HKMG technologies, the three reliability mechanisms that limit further inversion thickness caling are PositiveBTI (PBTI), NegativeBTI (NBTI), and nTime-dependent dielectric breakdown. PBTI and NBTI are fundamental degradation mechanisms in which charges are generated or trapped within the gate dielectric stack and its interfaces with the substrate and the metal gate. NBTI is composed of two essentially independent charge creation mechanisms: hole trapping in the bulk of the interfacial layer and interface generation.
