Integrated
memory circuits, key components in thousands of electronic and computer products, have recently been made using ferroelectric memory transistors, which offer faster write cycles and lower power requirements than over conventional floating-gate transistors. One problem that hinders the continued down-scaling of conventional ferroelectric memory transistors is the
vulnerability of their gate insulations to failure at thinner dimensions. Accordingly, the inventors devised unique ferroelectric gate structures, one of which includes a high-integrity
silicon-
oxide insulative layer, a doped
titanium-
oxide layer, a weak-ferroelectric layer, and a control gate. The doped
titanium-
oxide layer replaces a
metal layer in the conventional ferroelectric gate structure, and the weak-ferroelectric layer replaces a conventional ferroelectric layer. These replacements reduce the
permittivity mismatch found in conventional gate structures, and thus reduce stress on gate insulation
layers, thereby improving reliability of ferroelectric memory transistors, particularly those with thinner gate insulation.