Deposition of SiN_x Films with Controlled Residual Stress from SiH₄-NH₃-He Gaseous Mixture in Inductively Coupled Plasma

Abstract

We have studied residual mechanical stresses of SiNx films deposited on silicon substrates from a SiH4-NH3-He gaseous mixture in an inductively coupled plasma reactor at a deposition temperature of 150 °C. By varying the flow rate ratio of the reacting gases, the power of the plasma source and the pressure in the reaction chamber, it is possible to obtain SiNx films with tensile or compressive residual stresses. The stress drift was estimated within four weeks after film deposition. It has been shown that for nitride films with residual stresses initially close to zero, an increase in the level of compressive stresses to (–300) MPa is observed during storage.

Keywords

• silicon nitride
• vapor deposition
• high-density plasma
• mechanical stress
• refractive index