Stmicroelectronics S.r.l.

Barbara Crivelli

Mauro Alessandri

Nicola Zatelli

Elisabetta Palumbo

Romina Zonca

Daniela Peschiaroli

A process for manufacturing a non-volatile memory cell having at least one gate region, the process including the steps of depositing a first dielectric layer onto a semiconductor substrate; depositing a first semiconductor layer onto the first dielectric layer to form a floating gate region of the memory cell; and defining the floating gate region of the memory cell in the first semiconductor layer. The process further includes the step of depositing a second dielectric layer onto the first conductive layer, the second dielectric layer having a higher dielectric constant than 10. Also disclosed is a memory cell integrated in a semiconductor substrate and having a gate region that has a dielectric layer formed over a first conductive layer and having a dielectric constant higher than 10.

Manufacturing process of a semiconductor non-volatile memory cell

A process manufactures an interpoly dielectric layer for non-volatile memory cells of a semiconductor device with an interpoly dielectric layer. The process begins with forming the tunnel oxide, and hence the amorphous or polycrystalline silicon layer, using conventional techniques. After the amorphous or polycrystalline silicon layer is surface cleansed and passivated, the surface of the polycrystalline layer is nitrided directly by using radical nitrogen. This is followed by the formation of the interpoly dielectric, either as an ONO layer or a single silicon layer, by means of the CVD technique. Masking to define the floating gate may be performed immediately before or after the direct nitridation step is carried out. The equivalent electrical thickness of the interpoly dielectric, obtained by combining the nitride oxide layer and by the following dielectric, does not exceed 130 Angstroms in either the ONO layer or the single silicon layer embodiment.

Manufacturing process of an interpoly dielectric structure for non-volatile semiconductor integrated memories

Active areas and body regions are formed in a substrate for forming low voltage MOS transistors, high voltage MOS transistors, and EPROM cells. A thermal oxide layer is formed on the substrate, and a first polycrystalline silicon layer is formed on the thermal oxide layer. The polycrystalline silicon layer is selectively removed to form the floating gate electrodes of the EPROM cells, and the source and drain regions of the EPROM cells are also formed. The active areas for the high voltage MOS transistors are exposed, and a layer of high temperature oxide is formed and nitrided. The active area for the low voltage MOS transistors are exposed, and a layer of thermal oxide is formed on the exposed areas. A second polycrystalline silicon layer is deposited, which is then selectively removed to form the gate electrodes of the low voltage and high voltage MOS transistors, and the control gate electrodes of the EPROM cells.

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Milan, Italy

Barbara Crivelli