Radical oxidation process for fabricating a nonvolatile charge trap memory device

Abstract

A method for fabricating a nonvolatile charge trap memory device is described. The method includes subjecting a substrate to a first oxidation process to form a tunnel oxide layer overlying a polysilicon channel, and forming over the tunnel oxide layer a multi-layer charge storing layer comprising an oxygen-rich, first layer comprising a nitride, and an oxygen-lean, second layer comprising a nitride on the first layer. The substrate is then subjected to a second oxidation process to consume a portion of the second layer and form a high-temperature-oxide (HTO) layer overlying the multi-layer charge storing layer. The stoichiometric composition of the first layer results in it being substantially trap free, and the stoichiometric composition of the second layer results in it being trap dense. The second oxidation process can comprise a plasma oxidation process or a radical oxidation process using In-Situ Steam Generation.

What is claimed is: 
     
         1 . A memory device, comprising:
 a channel formed over a semiconductor material structure connecting a first and second diffusion regions, the channel being formed from a layer of semiconductor material;   a tunnel oxide disposed abutting the channel;   a multi-layer charge storing layer including a first nitride layer disposed adjacent to the tunnel oxide and a second nitride layer overlying the first nitride layer, the first nitride layer being substantially trap free and the second nitride layer being trap dense, wherein the first and second nitride layers have differing compositions of silicon, oxygen, and nitrogen; and   a blocking dielectric layer including high-temperature-oxide disposed adjacent to the second nitride layer.