Focused ion beam induced local modifications of the contact potential difference of n- and p-doped silicon

摘要

Kelvin probe microscopy (KPM) has been used to investigate n-doped and p-doped silicon processed with a Ga~+ focused ion beam (FIB) for doses up to 2.5 __ 10~(18) cm~(-2). KPM measurements reveal that FIB processing induces dose dependent, highly localized modifications of the contact potential difference (CPD) within the previously homogeneous silicon specimens. Significant characteristic differences in the CPD are observed between n- and p-doped silicon processed with a focused Ga~+ ion beam. A depletion-like zone is observed in the CPD between the pristine and Ga~+ implanted nano-volumes of n-type silicon which stabilizes once the implanted gallium concentration is in dynamic equilibrium. In contrast, a depletion-like region is not observed in Ga~+ processed p-type silicon, and the CPD across the Ga~+ processed and pristine regions of the specimen is ultimately equalized.