Stress in ion-implanted CVD Si3N4 films

Abstract

The compressive stress buildup caused in chemical‐vapor‐deposited (CVD) Si₃N₄ films by ion implantation is shown to be caused entirely by atomic collision effects, ionization effects being unimportant. The stress introduction rate is shown to be independent of CVD processing variables and O content of the film. The maximum attainable compressive stress change is 3.5×10¹⁰ dyn/cm², resulting in a maximum net compressive stress of 2×10¹⁰ dyn/cm² for films on Si where the as‐deposited films inherently have 1.5×10¹⁰ dyn/cm² tensile stress before ion implantation. Results are presented which show that O in the films inhibits thermal annealing of the ion‐implantation‐induced compressive stress. Results for introduction rate and annealing effects are presented in normalized form so that workers can use the effects for intentional stress level adjustment in the films to reduce probability of cracking and detachment.