Dresden 2014 – wissenschaftliches Programm
HL 78.3: Vortrag
Mittwoch, 2. April 2014, 17:00–17:15, POT 251
Crystallization phenomena of germanium nano crystals in ZrO2 — •Maximilian Geyer1, Peter Seidel1, David Lehninger1, Volker Klemm2, Gerhard Schreiber2, and Johannes Heitmann1 — 1TUBAF, Institut für Angewandte Physik — 2TUBAF, Institut für Werkstoffwissenschaften
Due to the heightened interest of semiconductor nanocrystals in high-κ matrices the crystallization of germanium in ZrO2 was investigated. Germanium was especially interesting because of its smaller band gap and higher Bohr-radius then silicon and ZrO2 shows superior high-κ and dielectric properties and is of interest for optical and electrical applications.
All samples were prepared by a co-sputtering process of a superlattice containing pure ZrO2 and mixed Ge/ZrO2 layers. First different annealing processes combined with different capping layers to prevent the oxidation of germanium due to the oxygen conductivity of the matrix were tested. A Capping layer of SiO2 combined with a RTP annealing process gives the best results. Raman and photoluminescence spectroscopy show characteristic peaks after this processing which are connected to nanocrystalline structures.
Furthermore we found that a interface layer of silicon nitride in contrast to the natural silicon oxide transmits the crystal information of our silicon substrate to the layers of our superlattice and makes a continuous crystallization of germanium possible.
Further research will investigate different layer compositions and the possibility of lateral conductivity through the nano crystalline layers.