Process for making sol-gel deposited ferroelectric thin films insensitive to their substrates

A method for producing a thin film of a ferroelectric perovskite material comprising:

• a. providing a first substrate;
• b. selecting a first sol-gel perovskite precursor material wherein the crystallization of the first sol-gel perovskite precursor material to the perovskite phase is insensitive to the first substrate and wherein after heat treatment the material is isostructural to the second ferroelectric perovskite thin-film material of step (f);
• c. depositing a first layer of the first sol-gel perovskite precursor material;
• d. selecting a sol-gel perovskite precursor material wherein the crystallization of the second sol-gel perovskite precursor material is sensitive to the first substrate;
• e. depositing a second layer of the second sol-gel perovskite precursor material;
• f. heat-treating the deposited layers to form a first layer and a second layer of ferroelectric perovskite thin film material;
• and whereby the second layer of the selected second sol-gel perovskite precursor material after heat treatment has better perovskite crystallinity when deposited on the first layer than if the second layer had been deposited directly on the first substrate and heat treated.

A method for producing a thin film of a ferroelectric perovskite material comprising:

• a. providing a first substrate selected from the group consisting of fused silica (SiO.sub.2), silicon (Si), gallium arsenide (GaAs), alumina (Al.sub.2 O.sub.3), sapphire (single crystal Al.sub.2 O.sub.3), or any of the above substrates coated with platinum, gold, indium tin oxide, F-doped tin oxide, or any other material with metallic conductivity;
• b. depositing a first layer of a sol-gel perovskite precursor material of PbTiO.sub.3, or SrTiO.sub.3 ;
• c. heat-treating the first deposited layer to form a perovskite thin film material;
• d. depositing a second layer of a sol-gel perovskite precursor material of:
• lead zirconate titanate (Pb(Zr,Ti)O.sub.3 or PZT), lead zirconate (PbZrO.sub.3), lead lanthanum titanate ((Pb,La)TiO.sub.3), lead lanthanum zirconate ((Pb,La)ZrO.sub.3), lead lanthanum zirconate titanate ((Pb,La)(Zr,Ti)O.sub.3 or PLZT), lead magnesium niobate (Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3, lead zinc niobate (PbZn(.sub.1/3 Nb.sub.2/3)O.sub.3), barium titanate (BaTiO.sub.3), strontium barium titanate ((Sr,Ba)TiO.sub.3), barium titanate zirconate (Ba(Ti,Zr)O.sub.3), potassium niobate (KNbO.sub.3), potassium tantalate (KTaO.sub.3), and potassium tantalate niobate (K(Ta,Nb)O.sub.3);
• e. heat-treating the second deposited layer to form a perovskite material;
• and whereby the second layer of sol-gel perovskite precursor material after heat treatment has better perovskite crystallinity when deposited on the first layer than if it had been deposited directly on the first substrate and heat treated.

A method for producing a thin film of a ferroelectric perovskite material comprising:

• a. providing a first substrate selected from the group consisting of fused silica (SiO.sub.2), silicon (Si), gallium arsenide (GaAs), alumina (Al.sub.2 O.sub.3), sapphire (single crystal Al.sub.2 O.sub.3), or any of the above substrates coated with platinum, gold, indium tin oxide, F-doped tin oxide, or any other material with metallic conductivity;
• b. depositing a first layer of a sol-gel perovskite precursor material of PbTiO.sub.3, or SrTiO.sub.3 ;
• c. depositing a second layer of a sol-gel perovskite precursor material of lead zirconate titanate (Pb(Zr,Ti)O.sub.3 or PZT), lead zirconate (PbZrO.sub.3), lead lanthanum titanate ((Pb,La)TiO.sub.3), lead lanthanum zirconate ((Pb,La)ZrO.sub.3), lead lanthanum zirconate titanate ((Pb,La)(Zr,Ti)O.sub.3 or PLZT), lead magnesium niobate (Pb(Mg.sub.1/3 Nb.sub.2/3 O).sub.3) lead zinc niobate (Pb(Zn.sub.1/3 Nb.sub.2/3)O.sub.3) barium titanate (BaTiO.sub.3), strontium barium titanate ((Sr,Ba)TiO.sub.3), barium titanate zirconate (Ba(Ti,Zr)O.sub.3), potassium niobate (KNbO.sub.3), potassium tantalate (KTaO.sub.3), or potassium tantalate niobate (K(Ta,Nb)O.sub.3);
• d. heat-treating the deposited layers to form a perovskite thin film material;
• and whereby the second layer of sol-gel perovskite precursor material after heat treatment has better perovskite crystallinity when deposited on the first layer than if it had been deposited directly on the first substrate and heat treated.