Flash memory and fabrication method thereof

摘要

A flash memory fabrication method includes: providing a substrate having a plurality of floating gate structures separated by trenches, which includes at least a source trench and a drain trench, and source/drain regions; forming a metal film on the substrate and on the floating gate structures; performing a thermal annealing process on the metal film to form a first silicide layer on the source regions and a second silicide layer on the drain regions; removing portions of the metal film to form a metal layer on the bottom and lower sidewalls of the source trench and contacting with the first silicide layer, and forming a dielectric layer on the substrate and the floating gate structures, covering the source trench and the drain trench. Further, the method includes forming a first conducting structure and one or more second conducting structures in the dielectric layer. The first conducting structure is on the metal layer in the source trench, the second conducting structures are on the second silicide layer, and adjacent first conducting structure and second conducting structure have a predetermined distance.

主权项

1. An flash memory fabrication method, comprising:
providing a substrate having a plurality of floating gate structures separated by trenches, including at least a source trench and a drain trench, wherein source regions are formed in the substrate at bottom of the source trench and drain regions are formed in the substrate at bottom of the drain trench; forming a metal film on the substrate and on the floating gate structures; performing a thermal annealing process on the metal film to diffuse metal ions of the metal film into the substrate to form a first silicide layer on the source regions and a second silicide layer on the drain regions; removing portions of the metal film to form a metal layer on the bottom and lower sidewalls of the source trench and contacting with the first silicide layer; forming a dielectric layer on the substrate and the floating gate structures, the dielectric layer covering the source trench and the drain trench; and forming a first conducting structure and one or more second conducting structures in the dielectric layer, wherein the first conducting structure is on a surface of the metal layer in the source trench, the second conducting structures are on a surface of the second silicide layer, and adjacent first conducting structure and second conducting structure have a predetermined distance.