In situ laser processing of high critical transition temperature superconductor and semiconductor heterostructures

In-situ single chamber laser processing of high T{dollar}sb{lcub}rm c{rcub}{dollar} YBa{dollar}sb2{dollar}Cu{dollar}sb3{dollar}O{dollar}sb{lcub}rm 7-delta{rcub}{dollar} (YBCO) thin films on Si(100) substrates with yttria-stabilized zirconia (YSZ) and magnesium oxide (MgO) buffer layers, has been developed using multitarget deposition system. Similarly, YBCO thin films were deposited on GaAs(100) substrates with YSZ buffer layer. A silicon cleaning system was designed and constructed as the oxide free silicon surface is essential for the synthesis of epitaxial films. Both buffer layers and YBCO films were deposited sequentially on atomically cleaned silicon substrates using a KrF excimer laser ({dollar}lambda{dollar} = 248 nm) at an optimized substrate temperature. The films were characterized using X-ray diffraction, Rutherford backscattering, Auger electron microscopy, four point probe ac resistivity measurements, scanning and transmission electron microscopy. The nature of buffer layers has been studied in detail and was found be polycrystalline and epitaxial depending upon the processing parameters. Details of thin film growth were investigated as a function of substrate and laser parameters.; In the second part of this research, we investigated the formation of TiSi{dollar}sb2{dollar} and CoSi{dollar}sb2{dollar} thin films on Si(100) substrates using laser physical vapor deposition technique. The films were deposited from solid targets of TiSi{dollar}sb2{dollar} and CoSi{dollar}sb2{dollar} in vacuum with the substrate temperature optimized at 600{dollar}spcirc{dollar}C. The room-temperature resistivities were found to be 16 and 23 {dollar}muOmega{dollar}cm, for TiSi{dollar}sb2{dollar} and CoSi{dollar}sb2{dollar}, respectively. We optimized the processing parameters to get particulate free surface of these silicide films. The interface between film and substrate was found to be smooth and sharp and no perceptible interdiffusion was observed. Correlations of microstructure with electrical properties of these films were investigated as a function of deposition parameters. CoSi{dollar}sb2{dollar} thin film was used to measure the contact resistance between the film and Si substrate. Silicide contacts to p+-Si were ohmic in nature and showed a linear behavior over a large range of current density. Initial electrical measurements on contact characteristics are described.