Physical analysis of breakdown in high-κ/metal gate stacks using TEM/EELS and STM for reliability enhancement (invited)

In this invited paper, we demonstrate how physical analysis techniques that are commonly used in integrated circuits failure analysis can be applied to detect the failure defects associated with ultrathin gate dielectric wear-out and breakdown in high-κ materials and investigate the associated failure mechanism(s) based on the defect chemistry. The key contributions of this work are perhaps focused on two areas: (1) how to correlate the failure mechanisms in high-κ/metal gate technology during wear-out and breakdown to device processing and materials and (2) how the understanding of these new failure mechanisms can be used in proposing "design for reliability" (DFR) initiatives for complex and expensive future CMOS nanoelectronic technology nodes of 22 nm and 15 nm. Hf-based high-κ materials in conjunction with various gate electrode technologies will be used as main examples while other potential high-κ gate materials such as cerium oxide (CeO₂) will also be demonstrated to further illustrate the concept of DFR.