FERROELECTRIC THIN FILM, SUBSTRATE COATED WITH FERRORELECTRIC THIN FILM, CAPACITOR STRUCTURE ELEMENT AND DEPOSITION OF FERROELECTRIC THIN FILM

摘要

PROBLEM TO BE SOLVED: To attain a high residual spontaneous polarization by shifting the compositional ratio of Bi/Ti in a ferroelectric thin film of ferroelectric crystal containing Bi, Ti and O as constitutive elements from stoichiometric composition thereby making the residual spontaneous polarization coercive electric field controllable. SOLUTION: Surface of a silicon substrate 1, i.e., a silicon single crystal water, is thermally oxidized to form a silicon oxide layer 2. An adhesive layer 3 and a lower electrode layer 4 are then formed thereon by sputtering. Subsequently, a titanium oxide butter layer 5, a crystal nucleus layer 6, and a ferroelectric thin film 7 of ferroelectric crystal containing Bi, Ti and O as constitutive elements and having the compositional ratio of Bi/Ti shifted from stoichiometric composition are formed further thereon. According to the structure, the residual spontaneous polarization and coercive electric field are made controllable and a high residual spontaneous polarization can be attained.