Memory with high dielectric constant antifuses and method for using at low voltage

Abstract

A memory array having memory cells comprising a diode and an antifuse can be made smaller and programmed at lower voltage by using antifuse materials having higher dielectric constant and higher acceleration factor than silicon dioxide, and by using diodes having lower band gaps than silicon. Such memory arrays can be made to have long operating lifetimes by using the high acceleration factor and lower band gap materials. Antifuse materials having dielectric constants between 5 and 27, for example hafnium silicon oxynitride or hafnium silicon oxide are particularly effective. Diode materials with band gaps lower than silicon, such as germanium or a silicon-germanium alloy are particularly effective.

Description

RELATED APPLICATIONS [0001] This application relates to concurrently filed U.S. application Ser. No. ______ (attorney docket number MA-153) by N. Johan Knall, entitled “REVERSE-BIAS METHOD FOR WRITING MEMORY CELLS IN A MEMORY ARRAY”; and to U.S. application Ser. No. ______, (attorney docket number MA-154) by James M. Cleeves, entitled “MEMORY CELL WITH HIGH-K ANTIFUSE FOR REVERSE BIAS PROGRAMMING”; all filed herewith and incorporated herein by reference.BACKGROUND OF THE INVENTION [0002] The invention relates to programming and reading an array of nonvolatile memory cells each comprising a diode in series with an antifuse. [0003] Integrated circuit memories are typically large arrays of memory cells connected between bit lines and word lines. In order to achieve reliable programming and reading of the memory cells within the array, memory cells selected to be programmed or read must be isolated from memory cells that are not selected. Also, as it becomes increasingly important to mi...

AI Technical Summary

Benefits of technology

The present invention is about methods of forming and programming an array of nonvolatile memory cells each comprising an antifuse in series with a diode. The invention takes advantage of the one-way nature of the diode and uses materials that allow for lower voltage operation. By using a material with a higher dielectric constant than silicon dioxide, the vertical dimension of the memory cell can be reduced, and the write voltage and read voltage can be reduced. The invention also ensures that unselected memory cells are not programmed or otherwise disturbed. The technical effects of the invention are that it reduces power consumption and allows for reliable reading and writing of memory cells at lower voltages.

Problems solved by technology

But antifuses and diodes made from films of silicon dioxide have already been made just a few atoms thick, and can not be made thinner.

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