Quantitative Kelvin probe force microscopy imaging on locally doped Si

Failure analysis and optimization of nanoelectronic devices require knowledge of their electrical properties. Kelvin probe force microscopy (KPFM) is a standard technique for the investigation of the surface
potential. Since KPFM was developed in 1991 the measured KPFM signal was attributed to the contact potential difference (CPD) between conductive probe and sample. We show that the CPD is not suitable to describe the measured Kelvin bias in semiconductors quantitatively and introduce a unique KPFM model [1] which successfully correlates the measured Kelvin bias with the difference between Fermi energy and respective band edge. Quantitative dopant profiling is demonstrated on cross-sectionally prepared Si epilayer structures and on a Si dynamic random access memory cell.
[1] C. Baumgart, M. Helm, H. Schmidt, Phys. Rev. B 80 (2009) 085305.