High quality YBa2Cu3O7-x/SrTiO3 bilayers for superconducting electric field effect transistor

Abstract

We report the YBa2Cu3O7-x/SrTiO3 (YBCO/STO) bilayer structure to prevent the deterioration of superconductivity of YBCO channel layer having a grain-boundary junction in superconducting field effect transistor. Two types of method were used, such as the 20 nm-thick STO capping layer and the 100 nm-thick PBa2Cu3O7-x buffer layer deposition. Transition temperature of 50 nm-thick ultrathin YBCO channel layer on STO bi-crystal substrate deposited by these method increased to 80 K owing to the sufficient oxidation and the relaxation of film stress in YBCO channel layer.