Monday, August 21, 2006

US Patent 7092287 - SiN Nanodot Memory

The use of nanodots as charge storage elements is a proposed technique to overcome the problems of charge retention in nanoscale floating gate memory devices. Si has been used to form such nanodots but is subject to oxidation. This patent proposes using SiN nanodots and fabricating the nanodots by exposing silicon nanodots to nitrogen containing gas. Claims 1,17,23, and 28 are representative.

1. A method for the formation of silicon nitride nanodots on a semiconductor substrate, the method comprising the steps of: forming silicon nanodots on the semiconductor substrate; and nitriding the silicon nanodots by exposing the silicon nanodots to a nitrogen containing gas.

17. A method for forming a memory device, comprising: depositing a discontinuous silicon layer on a substrate; and nitriding the discontinuous silicon layer.

23. A non-volatile memory device comprising: a semiconductor substrate; a plurality of silicon nitride nanodots across an area of the substrate, the silicon nitride nanodots having an average size between about 1 nm and 100 nm and covering between about 10% and 50% of the area of the substrate.

28. An integrated circuit, comprising a substrate having a plurality of silicon nitride nanodots, wherein a core region of at least some of the nanodots has a lower nitrogen concentration than a surface region of the at least some of the nanodots.