Sectional structures and electrical properties of ultrathin NbN/MgO bilayers on Si(100)

Abstract
NbN/MgO bilayers deposited on Si(100) substrates by rf‐sputtering were studied using cross‐sectional transmission electron microscopy (XTEM). The XTEM results reveal that the 10‐nm‐thick MgO layer forms two layers of different structures, i.e., an amorphous layer (∼4 nm) and a highly (100) oriented polycrystalline layer (∼6 nm). We also found that the structure of MgO underlayers exhibits a strong effect on Tc of on‐deposited NbN layers.