Strain Modification of PECVD Nitride By Plasma Immersion Ion Implantation Processes

The impact of Plasma Immersion Ion Implantation (PIII) processes with various species (hydrogen, helium and nitrogen) on the stress of a tensile PECVD nitride film was evaluated. Ellipsometry measurements indicated no consumption of the nitride but a change in the optical index, signaling a material modification. The initial stress of the nitride was modified by PIII from tensile to mechanically neutral and even compressive. Hydrogen and nitrogen appeared to be more efficient to modify the stress than helium.