Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

Quantitative Kelvin probe force microscopy on semiconductors under ambient conditions

Baumgart, C.; Müller, A.-D.; Müller, F.; Helm, M.; Schmidt, H.

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. We present its applicability to locally doped semiconductors. Quantitative dopant profiling by means of KPFM is successfully shown on a conventional static random access memory (SRAM) cell and on cross-sectionally prepared Si epilayer structures by applying a recently introduced new explanation of the measured KPFM signal [1]. The presented KPFM model is also used to explain observed large conductivity differences in different Mn implanted and pulsed laser annealed Ge samples by revealing a strong variation of the Fermi level position on the µm scale in dependence on the annealing conditions [2].
In addition, the frequency dependence of the Kelvin bias above differently doped regions is discussed with respect to surface states and trapped charges in the thin oxide layer on top [3]. Using an active mixer, the excitation amplitude of the cantilever is almost independent of the operation frequency. As a result, KPFM measurements have to be performed at frequencies high enough so that the electrical properties of the locally doped semiconductor and not of the oxide layer are probed.

[1] C. Baumgart, M. Helm, H. Schmidt, Phys. Rev. B 80, 085305 (2009).
[2] S. Zhou, D. Bürger, A. Mücklich, C. Baumgart, W. Skorupa, C. Timm, P. Oesterlin, M. Helm, and H. Schmidt, Phys. Rev. B 81 (2010), 165204.
[3] F. Müller and A.-D. Müller, J. Vac. Sci. Techn. B 27, 969 (2009).

Related publications

  • Lecture (Conference)
    Nanofair 2010, 06.-07.07.2010, Dresden, Germany

Publ.-Id: 14373