Atomic layer deposition of sidewall spacers: Process, equipment and integration challenges in state-of-the-art logic technologies

Abstract

This paper discusses the properties of silicon nitride and silicon oxide spacer films from the perspectives of ALD (Atomic Layer Deposition) and MLD (Molecular Layer Deposition) techniques, precursor chemistries and compositional stability after implant anneals and spacer sculpting reactive ion etching processes. Advanced imaging techniques like EELS (Electron Energy Loss Spectroscopy) and SIMS (Secondary Ion Mass Spectrometry) techniques have been used to analyze sidewall spacer processes. Special attention has been paid to the microloading effect - The dependence of thin film deposition rate on pattern density. The effect of ALD deposition parameters on film electrical characteristics like dielectric breakdown and leakage are also delineated.