High polarization ferroelectric capacitors for integrated circuits

Abstract

One aspect of the invention relates to a method of manufacturing an integrated circuit comprising forming an array of ferroelectric memory cells on a semiconductor substrate, heating the substrate to a temperature near a Curie temperature of the ferroelectric cores, and subjecting the substrate to a temperature program, whereby thermally induced stresses on the ferroelectric cores cause a switched polarization of the cores to increase by at least about 25% as the cores cool to about room temperature. Embodiments of the invention include metal filled vias of expanded cross-section above and below the ferroelectric cores, which increase the thermal stresses on the ferroelectic cores during cooling.

Description

FIELD OF THE INVENTION [0001] The present invention relates generally to the field of integrated circuit manufacturing, and more particularly relates to ferroelectric RAM. BACKGROUND OF THE INVENTION [0002] Ferroelectric memory, and other types of semiconductor memory, are used for storing data and / or program code in personal computer systems, embedded processor-based systems, and the like. Ferroelectric memories are commonly organized in single-transistor, single-capacitor (1T1C) or two-transistor, two-capacitor (2T2C) configurations, in which data is read from or written to the device using address signals and various other control signals. The individual memory cells typically comprise one or more ferroelectric (FE) capacitors adapted to store a binary data bit, as well as one or more access transistors, typically MOS devices, operable to selectively connect the FE capacitor to one of a pair of complimentary bitlines, with the second bitline being connected to a reference voltage...

AI Technical Summary

Benefits of technology

The invention relates to a method and structure for manufacturing integrated circuits with ferroelectric memory cells. The method involves heating the substrate and subjecting it to a temperature program to induce stresses on the ferroelectric cores, which causes a switched polarization of the cores. This results in a higher switched polarization of the memory cells, allowing them to be made smaller and more densely packed. The structure includes metal plugs that add to the thermal stresses that reorient the domains during cooling. The technical effects of the invention include improved performance and reliability of the ferroelectric memory cells.

Problems solved by technology

A characteristic of the illustrated ferroelectric memory cell is that if the polarization of the ferroelectric is switched, the read operation is destructive and the sense amplifier must rewrite (onto that cell) the correct polarization value after the cell is read.

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