Plasma-deposited thin-film step coverage calculated by computer simulation

Thin-film growth contours from a diffuse source onto two-dimensional steps with varied sidewall angles and interstep aspect ratios have been computer simulated using string moving algorithms. Minimum fractional coverage occurs on the sidewall position nearest the step bottom in all cases. This position defines both the conductance limiting region for conductors and the point of voltage breakdown for dielectrics. The variations in minimum fractional coverage with changes in sidewall angle and step dimensional ratios indicate the importance and limitations of sidewall tapering for ‘‘small’’ geometries.