Pulsed laser deposition of HTSC Bi(Pb)SrCaCuO thin films and buffer layers on silicon substrates and application of solid state mass spectrometry in HTSC research

Up to now the deposition of HTSC BiSrCaCuO thin films with Tc(0) ≥ 80 K and jc ≥ 105 A/cm2 was successful only on inert single crystal substrates (for instance perovskites like SrTiO3 and NdGaO3). The task of this project was to investigate the possibilities of Pulsed Laser Deposition of BiSrCaCuO thin films on more reactive silicon substrates with buffer layers. Tc(R=0) of BiSrCaCuO films on silicon with YSZ and SrTiO3 buffer layer was determined to be at least 10 K lower compared to films on inert single crystal substrates due to the necessary high formation temperature of the superconducting perovskite structure. The Tc(0) of 70 K measured by our group is the highest published Tc(0) for the BiSrCaCuO/YSZ/Si system to our knowledge up to now. For the first time HTSC thin film systems were investigated by SNMS depth profiling in more detail. All analysed systems (except on SrTiO3 substrates) showed an onset of the undesired interdiffusion processes at a substrate temperature of 750-800 C. Therefore, a technological application of BiSrCaCuO HTSC thin films on silicon substrates seems to be impossible at present. (orig.)