Evaluation of integrity and barrier performance of atomic layer deposited WNxCy films on plasma enhanced chemical vapor deposited SiO2 for Cu metallization

Abstract

The nucleation and growth of WNxCy films deposited by atomic layer deposition (ALD) on plasma enhanced chemical vapor deposited (PECVD) SiO2 is characterized as a function of the number of ALD cycles using transmission electron microscopy analysis. The island growth of isolated WNxCy nanocrystals is directly observed at the early stages of film growth. The nucleation of the WNxCy film can be significantly enhanced by NH3 plasma treatment before the deposition of WNxCy. The capacitance-voltage measurements conducted after bias-temperature stressing reveals that an ALD-WNxCy film deposited with a thickness of approximately 5.2nm on the NH3 plasma-treated PECVD SiO2 shows good diffusion barrier performance against Cu migration.