Multiphonon-electron coupling enhanced defect generation and breakdown mechanism in MOL new spacer dielectrics for 7nm/5nm technology nodes and beyond

We investigate multiphonon-electron coupling enhanced defect generation process and breakdown (BD) in middle-of-line (MOL) spacer dielectrics (Si3N4, SiBCN, and SiOCN). Rather than traditional Poole-Frenkel process, we report inelastic multiphonon assisted tunneling plays a key role in conduction process in these defective dielectrics in both initial and post-stress electron conduction. More importantly, we demonstrate defect generation process follows a universal process independent of thickness among these seemingly very different dielectrics. We show multiphonon-electron coupling is responsible for the enhanced defect generation rate due to high-energy electrons at the anode, thus triggering to specie-release induced BD.