Observation of SiO ₂ thickness variations on Si using AFM and SCM

Thickness variations of silicon dioxide was observed by the combined Atomic Force Microscopy (AFM) and nanoscopic Scanning Capacitance Microscopy (SCM). The capacitance was measured at the frequency of 915 MHz with the resonance circuit A/4 away from the AFM sensor. The spatial variations of the oxide thickness and dopant profile on the masked Si were imaged directly. The nanoscopic C-V reveals the same trends as that of macroscopic. Bias dependence of the measured capacitance on dopant profile in masked Si substrates was observed.