In-situ analysis of ion-induced physicochemical change of Si surface by secondary electron yield detection

We report the variation of secondary electron yield with ion fluence during 10 keV N⁺¹ and Ar⁺¹ ions bombardment on a Si (1 0 0) surface at normal and oblique incidence. The initial high secondary electron yield from Si surface is observed due to the native oxide layer on Si for both nitrogen and argon ion bombardment. The secondary electron yield is expected to decrease and stabilize for continue ion bombardment, which is observed for the argon ion irradiation. However, a significant variation of the electron yield with continuing nitrogen ion bombardment is observed. Ex situ measurement of ion bombarded surfaces by Atomic Force Microscope shows that the variation of secondary electron yield is correlated with the surface topography development due to ion bombardment. Also, the reaction of the projectile with target atom alters the secondary electron emission in case of N⁺ ion bombardment. The mean free path length of the secondary electron is estimated using the Parilis-Kishinevsky theory and the variation is presented. Real-time physicochemical changes of Si surface due to low energy ion bombardment have been probed in-situ by monitoring the secondary electron emission yield measurements.