A semiconductor element, a semiconductor sensor, and a semiconductor
memory element are provided, in which an MFMIS structure having a lower
electrode and an integrated circuit can be integrated. An epitaxially
grown .gamma.-Al.sub.2O.sub.3 single crystal film (2) is disposed on a
semiconductor single crystal substrate (1), and an epitaxial single
crystal Pt thin film (3) is disposed on the .gamma.-Al.sub.2O.sub.3
single crystal film (2).