Influence of photoperturbation on the characterization accuracy of scanning capacitance microscopy [MOSFET example]

Due to the photoperturbation induced by the atomic force microscopy laser beam, typical scanning capacitance microscopy (SCM) may produce false differential capacitance images of carrier distribution and electrical junctions. For a real MOS device, the photoperturbation can lead to a broadened source/drain region and narrower effective channel length (L/sub eff/). The photoperturbation also leads to many difficulties in employing SCM to investigate the influence of annealing processes on electrical junctions. It is revealed that the photoperturbation-induced errors in the measurements of L/sub eff/ and electrical junction width may be up to 11.2% and 50%, respectively.