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 th eoretical equations indicate that the etch rate for lightly doped sili con is independent of donor impurity concentration, whereas the etch r ate for heavily doped silicon is increased with an increase in donor i mpurity concentration. Numerical calculations of the etch rate as a fu nction of donor impurity concentration are made with some typical valu es of the parameters in the equations.