Method of fabricating dual PCRAM cells sharing a common...

Details Method of fabricating dual PCRAM cells sharing a common... Method of fabricating dual PCRAM cells sharing a common...

2001-08-27

2004-05-18

Pham, Long (Department: 2814)

Semiconductor device manufacturing: process

Making field effect device having pair of active regions...

Having insulated gate

C438S095000, C438S102000, C438S381000

Reexamination Certificate

active

06737312

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a PCRAM device which utilizes a chalcogenide glass memory cell to store a memory state. More particularly, the invention relates to a way of fabricating memory cells in a PCRAM memory device to increase packing density.
BACKGROUND OF THE INVENTION
Recently chalcogenide glasses fabricated as fast ion conductors have been investigated as data storage memory cells for use in memory devices, such as DRAM memory devices. U.S. Pat. Nos. 5,761,115, 5,896,312, 5,914,893, and 6,084,796 all describe this technology and are incorporated herein by reference. The storage cells are called programmable metallization cells, also known as PCRAM cells. One characteristic of such a cell is that it typically includes a fast ion conductor such as a chalcogenide metal ion and a cathode and anode spaced apart on a surface of the fast ion conductor. Application of a voltage across the cathode and anode causes growth of a non-volatile metal dendrite which changes the resistance and capacitance of the cell which can then be used to store data.
For this technology to be used on a mass scale in memory devices it is necessary to fabricate large numbers of memory cells in a relatively small amount of integrated surface area.
SUMMARY OF THE INVENTION
The present invention provides a fabrication process and resulting structure which stacks at least two programmable metallization cells vertically in an integrated circuit. The cells can be accessed individually to provide vertical storage of two data bits in a given area of the integrated circuit.


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