Properties of silicon nitride films deposited by ECR plasma CVD.

Abstract

Correlations between deposition conditions and properties of silicon nitride films deposited by an electron-cyclotron-resonance (ECR) plasma CVD have been investigated. BHF etching rate can be minimized, independent of the microwave power, by the control of the flow ratio (SiH4/N2) and total flow rate (SiH4+N2). The refractive index of the films deposited by these conditions are approximately 2.0. The films deposited at SiH4 (10 sccm) and N2 (10 sccm) have an electric breakdown strength of more than 8 MV/cm, a dielectric constant (1 MHz) of 6.4-6.9, and an internal stress of more than 7 × 109 dyn/cm2.The compressive stress, tensile stress and stress-free films can be successfully deposited by controlling the deposition conditions.The properties of the annealed films have been also investigated. Internal stress changes little upto an annealing temperature of400°C, but strongly shifts toward the tention above 400°C.