METHOD FOR MANUFACTURING TWIN BIT STRUCTURE CELL WITH HAFNIUM OXIDE AND NANO-CRYSTALLINE SILICON LAYER

摘要

A method and system for forming a non-volatile memory structure. The method provides a semiconductor substrate and forms a gate dielectric layer overlying a surface region of the semiconductor substrate. A polysilicon gate structure is formed overlying the gate dielectric layer. The method subjects the polysilicon gate structure to an oxidizing environment to cause formation of a first silicon oxide layer overlying the polysilicon gate structure and formation of a second silicon oxide layer overlying a surface region of the substrate. A hafnium oxide material is formed overlying the first and second silicon oxide layers and filling the undercut region. The hafnium oxide material has a nanocrystalline silicon material sandwiched between a first hafnium oxide layer and a second hafnium oxide layer. The hafnium oxide material is selectively etched while a portion of it is maintained in an insert region in a portion of the undercut region.