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US 2003/0146466 A1Published application
Floating gate for memory and manufacturing method thereof
AssigneeWinbond Electronics Corp.
InventorHsiu-Ling Ku
Life of this patent
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Abstract
The present invention discloses a floating gate for memory of high gate coupling ratio and the method of manufacturing the same. It utilizes a continuously concave-convex surface formed on the floating gate, and by virtue of the increase of the surface area of which to increase the gate coupling ratio with a control gate and further to reduce the working voltages for programming and erasing.
Claims7
A floating gate of non-volatile memory, comprising:
- a silicon substrate including at least two trenches;
- an isolation oxide layer covering said at least two trenches and protruding from said silicon substrate;
- a tunneling oxide layer covering a region on said silicon substrate and beside both sides of said isolation oxide layer;
- a first polysilicon layer covering said tunneling oxide layer and having a concave-convex rugged surface;
- a dielectric layer covering said first polysilicon layer and said isolation oxide layer;
- and
- a second polysilicon layer covering said dielectric layer.
4 more elements
A method for manufacturing a floating gate of non-volatile memory, comprising the steps of:
- providing a silicon substrate including at least two trenches;
- forming an isolation oxide layer on said trenches and said isolation oxide layer protruding from said silicon substrate;
- forming a tunneling oxide layer on said silicon substrate and beside both sides of said isolation oxide layer;
- depositing a composite polysilicon layer on said tunneling oxide layer;
- etching said composite polysilicon layer so as to form a concave-convex rugged surface;
- annealing said composite polysilicon layer so as to form a first polysilicon layer;
- depositing a dielectric layer on said first polysilicon layer and said isolation oxide layer;
- and
- depositing a second polysilicon layer on said dielectric layer.
6 more elements
Dependencies are inferred from the claim text.