Method of fabricating a self-aligned non-volatile memory cell
First Claim
1. A method of fabricating a self-aligned non-volatile memory cell on a semiconductor substrate, said method comprising the steps of:
- forming a first insulating layer over said substrate;
forming a main floating gate region on said first insulating layer;
modifying a first portion of said first insulating layer next to a side of said main floating gate region to form a thin insulating region, said thin insulating region being thinner than a second portion of said first insulating layer under said main floating gate region;
forming a small sidewall spacer over said thin insulating region;
forming a second insulating layer over said first insulating layer and over said small sidewall spacer;
removing a portion of said second insulating layer and said thin insulating region over said main floating gate region to expose a surface on top of said main floating gate region;
forming a thin connecting layer over and in physical contact with both said small sidewall spacer and said main floating gate region, said thin connecting layer contacting said main floating gate region via said surface, whereby said small sidewall spacer is electrically connected to said main floating gate region, and whereby said main floating gate region, said small sidewall spacer and said thin connecting layer form a floating gate of said non-volatile memory cell;
forming a third insulating layer over at least said floating gate; and
forming a control gate over said second insulating layer and above at least said floating gate.
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Abstract
Disclosed is a self-aligned non-volatile memory cell comprising a small sidewall spacer electrically coupled and being located next to a main floating gate region. Both the small sidewall spacer and the main floating gate region are formed on a substrate and both form the floating gate of the non-volatile memory cell. Both are isolated electrically from the substrate by an oxide layer which is thinner between the small sidewall spacer and the substrate; and is thicker between the main floating gate region and the substrate. The small sidewall spacer can be made small; therefore, the thin oxide layer area can also be made small to create a small pathway for electrons to tunnel into the floating gate.
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Citations
12 Claims
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1. A method of fabricating a self-aligned non-volatile memory cell on a semiconductor substrate, said method comprising the steps of:
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forming a first insulating layer over said substrate;
forming a main floating gate region on said first insulating layer;
modifying a first portion of said first insulating layer next to a side of said main floating gate region to form a thin insulating region, said thin insulating region being thinner than a second portion of said first insulating layer under said main floating gate region;
forming a small sidewall spacer over said thin insulating region;
forming a second insulating layer over said first insulating layer and over said small sidewall spacer;
removing a portion of said second insulating layer and said thin insulating region over said main floating gate region to expose a surface on top of said main floating gate region;
forming a thin connecting layer over and in physical contact with both said small sidewall spacer and said main floating gate region, said thin connecting layer contacting said main floating gate region via said surface, whereby said small sidewall spacer is electrically connected to said main floating gate region, and whereby said main floating gate region, said small sidewall spacer and said thin connecting layer form a floating gate of said non-volatile memory cell;
forming a third insulating layer over at least said floating gate; and
forming a control gate over said second insulating layer and above at least said floating gate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification