Gs. Hwang et Kp. Giapis, THE INFLUENCE OF SURFACE CURRENTS ON PATTERN-DEPENDENT CHARGING AND NOTCHING, Journal of applied physics, 84(2), 1998, pp. 683-689
Surface charge dissipation on insulator surfaces can reduce local char
ging potentials thereby preventing ion trajectory deflection at the bo
ttom of trenches that leads to lateral sidewall etching (notching). We
perform detailed Monte Carlo simulations of pattern-dependent chargin
g during etching in high-density plasmas with the maximum sustainable
surface electric field as a parameter. Significant notching occurs for
a threshold electric field as low as 0.5 MV/cm or 50 V/mu m, which is
reasonable for the surface of good insulators. The results support pa
ttern-dependent charging as the leading cause of notching and suggest
that the problem will disappear as trench widths are reduced. (C) 1998
American Institute of Physics. [S0021-8979(98)04614-3]