Regensburg 2007 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 28: Silicon Thin Films and Interfaces
DS 28.5: Vortrag
Freitag, 30. März 2007, 12:30–12:45, H32
Influence of in-situ phosphorus doping on crystal quality of MBE grown silicon — •Ulrich Abelein, Lothar Höllt, Torsten Sulima, and Ignaz Eisele — Universität der Bundeswehr München, Institut für Physik, Werner-Heisenberg-Weg 39, 85577 Neubiberg
Molecular beam epitaxy (MBE) is a method for the epitaxial growth of silicon, which is very suitable for research applications as it allows in-situ doping, variation of layer thickness from a few to several hundred nanometers and changes of process parameters like growth rate and temperature over a wide range to optimise properties of grown layers. But especially the realization of extremely high doped layers, especially n-type with thickness of more than 50 nm, is difficult due to segregation and diffusion.
We investigated the crystal quality of highly phosphorus doped (up to 1020 cm−3) monocrystalline silicon layers with thickness of several 100 nm. Layers with various phosphorus concentrations were grown at temperatures between 200∘C and 400∘C to find a good trade off between crystal quality and achievable doping level. The analysis was done by secondary ion mass spectroscopy (SIMS) and scanning electron microscopy (SEM) after HF:C2H4O3 etching. The result of this work was a process window for the growth of nearly defect free layers with homogenous phosphorus doping up to 1019 cm−3 and thickness above 300 nm.