METHOD OF MAKING AN INTEGRATED FERROELECTRIC DEVICE, AND DEVICE PRODUCED THEREBY

A combined integrated circuit/ferroelectric memory device using Phase III potassium nitrate as the ferroelectric material and which appears in the final device only at the crossover points of the top and bottom electrodes. The method of fabrication may use ion milling and ashing off of remaining resist. A method of making an integrated ferroelectric device comprising the steps of: (a) forming a first non-conductive layer (73) close to decode circuitry (68) of an integrated circuit (60); (b) forming channels (74-80) through layer (73); (c) forming trenches (89-95) in layer (73) next to channels (74-80); (d) completely filling channels (74-80) and partially filling trenches (89-95) with a first metal (98); (e) filling voids in trenches (89-95) with a second non-conductive material (99); (f) planarizing the upper surface (100) of layer (73), metal (98), and material (99); (g) forming a second non-conductive layer (102) on surface (100); (h) forming passages (103-113) through layer (102) next to trenches (89-95); (i) forming a ferroelectric layer (116) to overlie layer (102) and part of metal (98); (j) forming a second metal (117) to overlie layer (116); (k) removing undesired parts of metal (117), layer (116), and layer (102); (l) forming a third metal layer to overlie the remainder (121) of metal (117) and of layer (102), and exposed portions (120) of layer (116) and of first metal (98); and (m) removing undesired portions of the third metal layer.