Regensburg 2004 – wissenschaftliches Programm

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O: Oberflächenphysik

O 14: Postersitzung (Adsorption an Oberflächen, Epitaxie und Wachstum, Organische Dünnschichten, Oxide und Isolatoren, Phasenübergänge, Rastersondentechniken, Struktur und Dynamik reiner Oberflächen)

O 14.78: Poster

Montag, 8. März 2004, 18:00–21:00, Bereich C

Detection of dopant profiles in silicon by scanning capacitance microscopy and related techniques: the role of the passivation layer — •Reinhard Beyer¹, Elke Beyreuther¹, Bernd Schmidt², Stefan Polzin³, and Jörg Weber¹ — ¹Technische Universität Dresden, Institut für Angewandte Physik, D-01062 Dresden — ²Forschungszentrum Rossendorf, Institut für Ionenstrahlphysik und Materialforschung, PF 510119, D-01314 Dresden — ³Fraunhofer-Institut für Photonische Mikrosysteme, Grenzstrasse 28, D-01109 Dresden

Scanning capacitance microscopy (SCM) was employed for the study of dopant profiles in silicon test structures. The samples were fabricated by implantation of boron and phosphorous into n-type silicon. The oxide mask for the implantation was shaped by photolithography. Hence, stripe patterns with a size of 2 µm of the implanted region and different widths of the interregion were obtained. The implantation dose was 5 × 10¹², 5 × 10¹³ and 5 × 10¹⁴ cm⁻² for both implanted ions. Samples with native oxide coverage and with a 7 nm thick silicondioxide layer were compared in this study. SCM measurements were performed in the contact-mode. We show, that the contrast of the SCM signal between differently doped regions depends not only on the dc bias applied during the scan, but also on charge instabilities and trapping effects. The latter appeared mostly for samples with native oxide and resulted in hysteresis effects which could be observed with local dC/dV vs. V spectroscopy. The charge instabilities are discussed in a MOS-model. The results are compared with scanning spreading resistance measurements and with non-contact SCM.