SURFACE ADSORPTION AND REACTION OF CHLORINE ON IMPURITY-DOPED Si USING AN ECR PLASMA

摘要

Surface adsorption and reaction of chlorine and impurity segregation on doped Si in the etching process by an electron-cyclotron-resonance (ECR) chlorine plasma have been investigated. The etch rate of undoped and P-doped Si is nearly equal to the square of the concentration of the Cl atom adsorbed on the etched surface in spite of the P concentration. On the other hand, in the case of B-doped Si, B segregation on the etched surface is observed, and the etching is suppressed by the segregated B atoms. Consequently, it is suggested that the anomalous etching of doped Si compared with that of undoped Si is caused by the concentration difference of the adsorbed Cl atom and the impurity segregation on the etched surface.