Mechanical Stress in SiNx Films Grown by High Density Plasma Enhanced Chemical Vapor Deposition
N.S.Koval’chuk,S.A.Demidovich,L.A.Vlasukova,I.N.Parkhomenko,F.F.Komarov
Abstract
Abstract—SiNx films with low mechanical stress have been grown in an inductively coupled plasma (ICP) reactor using a SiH4 + N2 + Ar gas mixture. Nitrogen-enriched SiNx films under compressive stress from –10 to –50 MPa have been obtained at [SiH4]/[N2] from 0.55 to 1.0 and an ICP source power of 600 W. All other deposition conditions being constant, raising the ICP source power leads to an increase in stress level from –125 MPa at 300 W to –625 MPa at 800 W. Varying the deposition temperature in the range 25–350°C has little effect on the stress level and refractive index of the films and the SiNx growth rate. We have assessed residual stress drift in the SiNx films during three weeks after deposition and the effect of deposition conditions on the percentage of oxygen in the films.