US 2008/0157172 A1 · Saddle Type Flash Memory Device and Fabrication Method Thereof

Abstract

The present invention relates to a nano-scale flash memory device having a saddle structure, and a fabrication method thereof. Particularly, the invention relates to a highly integrated, high-performance flash memory device having a saddle structure for improving the scaling-down characteristic and performance of the MOS-based flash memory device. According to the invention, a portion of an insulating film around a recessed channel is selectively removed to expose the surface and sides of the recessed channel. A tunneling insulating film is formed on the exposed surface and sides of the recessed channel. On the resulting structure, a floating electrode, an inter-electrode insulating film and a control electrode are formed, thus fabricating the device. Particularly when the floating electrode is made of an insulating nitride film or pluralities of nano-scale dots, an excellent memory device can be made without using an additional mask. According to the invention, the scaling-down characteristic of the device is excellent, and current drive capability can be greatly increased since a channel through which current can flow is formed on the surface and sides of the recessed channel. Also, the ability of the control electrode to control the channel can be enhanced, so that memory write/erase characteristics can be improved.

Claims35

Dependent claims

A flash memory device comprising:

a silicon substrate having formed thereon a wall-type silicon body connected with the substrate;
a first insulating film formed on the surface of the silicon substrate and the surface of the silicon body;
a nitride film formed on the first insulating film;
a second insulating film for element isolation formed on the nitride film so as to reach the surface level of the silicon body;
a charge storage node, a control electrode, an inter-electrode insulating film and a control electrode, sequentially formed on the resulting structure;
a region to be used as a channel, which is recessed from the surface of the silicon body to a reasonable depth;
the second insulating film being, if necessary, recessed from the surface to a reasonable depth;
the first insulating film and the nitride film being etched more than the recess width or depth of the silicon body;
a tunneling insulating film formed on the surface and sides of the recessed region of the silicon body;
a charge storage node, an inter-electrode insulating film and a control electrode sequentially formed on the resulting structure;
and
source/drain regions formed to a depth in the silicon body on both sides of the gate stack (consisting of a charge storage node, an inter-electrode insulating film, and a control electrode), and an insulating film spacer formed on both sides of the gate stack.

9 more elements

A method for fabricating a flash memory device, comprising the steps of:

forming on a silicon substrate a wall-type silicon body connected with the substrate;
forming a first insulating film on the surface of the silicon substrate and the surface of the silicon body;
forming a nitride film on the first insulating film;
forming a second insulating film for element isolation on the nitride film to be planarized to the surface level of the silicon body;
recessing the surface of the silicon body to a reasonable depth to form a region to be used as a channel, and if necessary, recessing the surface of the second insulating film to a reasonable depth;
etching the first insulating film and the nitride film more than the recess width or depth of the silicon body;
forming a tunneling insulating film on the surface and sides of the recessed region of the silicon body;
forming on the resulting structure a charge storage node, an inter-electrode insulating film and a control electrode, in order;
sequentially forming source/drain regions and a insulating film spacer on both sides of the control electrode;
and
forming on the resulting structure a silicide film, if necessary, and then an insulating film, a contact hole and a metal layer, in order.

8 more elements

Dependencies are inferred from the claim text.

Saddle Type Flash Memory Device and Fabrication Method Thereof

Life of this patent

Saddle Type Flash Memory Device and Fabrication Method Thereof

Life of this patent

Abstract

Claims35