Model for the dry etching of heavily doped n-type silicon by atomic fluorine in the absence of ion bombardment

Etch rate equations for heavily doped n-type silicon in the absence of ion bombardment are derived from a diffusion-controlled model. The theoretical equations indicate that the etch rate for lightly doped silicon is independent of donor impurity concentration, whereas the etch rate for heavily doped silicon is increased with an increase in donor impurity concentration. Numerical calculations of the etch rate as a function of donor impurity concentration are made with some typical values of the parameters in the equations.