DEPTH PROFILING OF BI-SR-CA-CU-O THIN-FILMS BY SECONDARY NEUTRALS MASS-SPECTROMETRY

Secondary neutrals mass spectrometry (SNMS) was used for the first time for detailed investigation of the elemental concentration depth profiles of Bi-Sr-Ca-Cu-O thin films on SrTiO3(110), MgO(100), YSZ(100) and Si(100) substrates with YSZ or SrTiO3 buffer layer's. All the high-temperature superconducting (HTSC) thin films and buffer layers have been prepared by in situ pulsed laser deposition (PLD). Strong indications were found for interdiffusion of Bi-Sr-Ca-Cu-O film, substrate (except SrTiO3 single crystals) and buffer layer if substrate temperature during the HTSC film deposition of 20 min duration exceeded 750-800-degrees-C. Therefore, T(c)(R=0) of Bi2Sr2Ca1Cu2O8+y films on silicon substrates with buffer layer is not higher than 70 K at present. SNMS depth profiling gives a more detailed insight into interdiffusion phenomena of thin film systems than other analytical techniques.