Mechanism of silicon etching in the presence of CF ₂, F, and Ar ⁺

Atomic scale mechanism of silicon etching in presence of CF ₂, fluorine (F), and Ar ⁺ was analyzed using molecular dynamics simulation. It was found that segregated layers of Si-C and SiF _x formed on silicon surfaces due to Ar ⁺ ion impact and ion-induced mixing. It was also found that carbon reaction with silicon in the SiC area increased the total atomic density in the Si-C layer top early three times the value observed in undistributed Si. The results show that the carbon slows down the etching rate on increasing the atomic density in Si-C layer.