High-Tc superconductors on buffered silicon: materials properties and device applications

Fabrication of Superconducting YBa2Cu3O7−x Thin Films on Si Wafer via YSZ/CeO2 buffer layers

“…Especially, substrate temperatures and film thicknesses had to be optimized precisely in order to minimize effects of large differences on thermal expansion coefficients and crystal lattice parameters between the YBCO and CeO 2 /YSZ/Si multilayer structures (see Table 1) and increase the crystallinity. In some cases, the deposited YBCO thin films on CeO 2 /YSZ/Si could have two in-plane orientations [16]. However, at the specific temperature, epitaxial growth of YBCO thin film with single-crystal alignment is possible with 45 • rotations of the crystal structure [15,16,19].…”

“…Because the similar device processing steps such as photolithography and selective etching of the layers can be used for Nb-based superconducting devices, Si wafers became the standard substrate materials in conventional low-T c (critical temperature) superconducting devices [2]. However, the case is not that straightforward for the fabrication of high-T c superconducting devices on Si because of many challenges caused by the properties of high-T c materials [14][15][16][17][18][19]. Since the hightemperature superconductor (HTS) materials become superconductor above the liquid nitrogen temperature, which is quite cheap and easy to handle, it would be very useful to fabricate HTS devices on Si by bringing the main advantages of the HTS materials and Si substrates together [3].…”

“…In order to overcome this problem, a chemically stable buffer layer with proper crystalline structure has to be used on Si. This layer is commonly made by a Y 2 O 3 + ZrO 2 (YSZ) material which has proper crystal lattice parameters and thermal expansion coefficients with Si (Table 1) [16]. However, this single buffer layer approach does not satisfy the requirements because of yielding very low device performances.…”

Superconductors: Processing of High‐ T C Bulk, Thin Film, and Wires

“…• C), with slow cooling, in a higher oxygen partial pressure of 500 mTorr to 700 mTorr to obtain superconductivity (38,39).…”

“…Pulsed Laser Deposition. Pulsed laser deposition has been successfully used to deposit HTS thin films for in-situ processing; PLD is designed to replicate target stoichiometry in the deposited thin films (38). A typical PLD system consists of an ultra high vacuum chamber containing fused quartz windows for in-situ spectroscopic investigations.…”