Dresden 2017 – wissenschaftliches Programm
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MI: Fachverband Mikrosonden
MI 8: Scanning Probe Microscopy (SPM)
MI 8.3: Vortrag
Donnerstag, 23. März 2017, 10:30–10:45, MER 02
Scanning Microwave Microscopy and its application to nanoscale dopant density determination — •Arne Buchter1, Johannes Hoffmann1, Dimitri Hapiuk2,3, Christophe Licitra2,3, Kevin Louarn4,5, Guilhem Almuneau4, and Markus Zeier1 — 1Federal Institute of Metrology, METAS, Lindenweg 50, CH-3003 Bern-Wabern — 2Univ. Grenoble Alpes, F-38000 Grenoble — 3CEA, LETI, MINATEC Campus, F-38054 Grenoble — 4LAAS-CNRS, Université de Toulouse, CNRS, UPS, Toulouse — 5LNE, 29 avenue Roger Hennequin, F-78197, Trappes
In Scanning Microwave Microscopy (SMM) an atomic force microscope (AFM) is interfaced with a vector network analyzer (VNA) allowing to simultaneously measure topography and complex material properties on the nanoscale. Depending on the impedance forming at the tip-sample interface, a fraction of the microwaves is reflected and detected by the VNA in terms of scattering parameter S11. Operation in the microwave regime with fields confined to the tip’s apex allows for spatial resolution down to 50 nm as well as subsurface sensing.
To enable extraction of dopant densities from semiconductor samples we present a fast and versatile algorithm based on classical VNA calibration. This algorithm models the influence of dopant density on tip-sample capacitance thus allowing nanoscale determination of dopant concentrations. As a proof-of-principle we present SMM results on an MBE-grown n-doped GaAs multilayer structure with dopant densities ranging from (1016 - 6·1018) cm−3 which are then compared to Secondary Ion Mass Spectroscopy (SIMS) data.