Berlin 2012 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 63: Devices I
HL 63.2: Talk
Wednesday, March 28, 2012, 15:15–15:30, EW 015
A new method for obtaining accurate capacitance-voltage curves in the presence of additional space charges — •Kay-Michael Günther1, Hartmut Witte2, Alois Krost2, Stefan Kontermann3, and Wolfgang Schade1,3 — 1Clausthal University of Technology, EFZN, Am Stollen 19B, 38640 Goslar, Germany — 2Otto-von-Guericke University Magdeburg, Institute for Experimental Physics,Universitätsplatz 2, 39106 Magdeburg, Germany — 3Fraunhofer Heinrich Hertz Institute, Am Stollen 19B, 38640 Goslar, Germany
Evaluating capacitance-voltage (C-V) curves is a powerful tool for obtaining doping concentration profiles. If the sample contains additional space charges like pn-junctions, defects, or Schottky barriers, the commonly used methods often deliver false results. The reason is that the capacitance of the investigated junction cannot be measured directly, but the impedance is interpreted in terms of an equivalent circuit (EC). We show that these commonly used ECs are only valid under special considerations and can easily produce false results. We present a new method which uses a more general approach based on whole impedance spectra instead of single impedances to acquire accurate C-V curves even in the presence of additional space charges. We compare our method with the conventional techniques and discuss its advantages and disadvantages.