Charge trapping dielectric structure for non-volatile memory

Abstract

An integrated circuit structure comprises a bottom dielectric layer on a substrate, a middle dielectric layer, and a top dielectric layer. The middle dielectric layer has a top surface and a bottom surface, and comprises a plurality of materials. Respective concentration profiles for at least two of the plurality of materials between the top and bottom surfaces are non-uniform and arranged to induce a variation in energy gap between the top and bottom surfaces. The variation in energy gap establishes an electric field between the top and bottom surfaces tending to oppose charge motion toward at least one of the top and bottom surfaces and prevent resultant charge leakage.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to charge trapping dielectric structures and to non-volatile memory based on such structures. [0003] 2. Description of Related Art [0004] Electrically programmable and erasable non-volatile memory technologies based on charge storage structures known as EEPROM and flash memory are used in a variety of modern applications. A number of memory cell structures are used for EEPROM and flash memory. As the dimensions of integrated circuits shrink, greater interest is arising for memory cell structures based on charge trapping dielectric layers, because of the scalability and simplicity of the manufacturing processes. Memory cell structures based on charge trapping dielectric layers include structures known by the industry names NROM, SONOS, and PHINES, for example. These memory cell structures store data by trapping charge in a charge trapping dielectric layer, such as silicon nitride. As neg...

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Benefits of technology

[0037] While the present invention is disclosed by reference to the preferred embodiments and examples detailed above, it is to be understood that these examples are intended in an illustrative rather than in a limiting sense. It is contemplated that modifications and combinations will readily occur to those skilled in the art, which modifications and combinations will be within the spirit of the invention and the scope of the following claims.

Problems solved by technology

One problem associated with charge trapping structures used in non-volatile memory is data retention.

However, leakage of trapped charge occurs in such devices due to defects in the materials which accumulate over long use, or which are inherent in the structures.

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