Plasma enhanced atomic layer deposition of SiN_x:H and SiO₂

As the nanoelectronics industry looks to transition to both three dimensional transistor and interconnect technologies at the <22 nm node, highly conformal dielectric coatings with precise thickness control are increasingly being demanded. Plasma enhanced chemical vapor deposition (PECVD) currently fills this role for most applications requiring low temperature processing but does not always meet step coverage and thickness precision requirements. The authors present results for a hybrid technique, plasma enhanced atomic layer deposition (PEALD), which utilizes typical PECVD process gases and tooling while delivering improved topography coverage and thickness control. Specifically, the authors show that alternating SiH₄ gas/N₂ plasma exposures applied in an atomic layer deposition sequence can be used to deposit SiN_x:H films in a self-limiting fashion with improved conformality and superior performance as a moisture barrier. PEALD of SiO₂ using alternating SiH₄ and CO₂ plasma exposures is further demonstrated.