Mechanistic understanding of Breakdown and Bias Temperature Instability in High-K Metal devices using inline Fast Ramped Bias Test

Reliability Qualification has historically been a time consuming affair, taking up several months in each technology node´s development cycle. The recent introduction of High-K/Metal Gates (HKMG) and the additional complexity they bring to the gate stack have placed increased demands on reliability and the reliability feedback for gate stack definition. It is demonstrated that these demands can be met with a Fast Ramped Bias Test. Applying these tests to a large variety of High-K/Metal Gate stacks, it is shown that Breakdown depends almost exclusively on time zero gate leakage. PBTI is found to depend predominantly on the Interface layer (IL) and High-K thickness, while NBTI depends most strongly on the nitrogen content in the IL.