Stmicroelectronics S.r.l.

Other

Elisabetta Palumbo

Paola Zuliani

Roberto Annunziata

Daniela Peschiaroli

Alfonso Maurelli

Nicola Zatelli

Fausto Piazza

Marina Scaravaggi

Cosimo Torelli

Barbara Crivelli

Daniele Zompi

Massimo Atti

A reference voltage generator for a matrix of non-volatile memory cells of the EEPROM type, comprises at least one array enabled by an access transistor. The array comprises at least one reference cell associated with a relative select transistor, the transistors and the cell being realized on a semiconductor substrate and having active regions delimited by suitable field oxide regions and covered by a tunnel oxide layer and comprising at least one floating gate realized by a first polysilicon layer and covered by a dielectric layer and by a second polysilicon layer. Advantageously, the floating gate of the reference cells is contacted by a first contact terminal connected to a discharge transistor for the periodical discharge of possibly present charges. A process manufactures such a voltage generator.

Reading voltage generator for a non-volatile EEPROM memory cell matrix of a semiconductor device and corresponding manufacturing process

A process for manufacturing a matrix of non volatile memory cells includes forming a floating gate transistor and a cell selection transistor in a first active area, and a byte selection transistor in a second active area. A multilayer structure is deposited, comprising a gate oxide layer, a first polysilicon layer, a dielectric layer, and a second polysilicon layer. The multilayer structure is defined to form two bands, the first band defining gate regions of the byte selection transistor and the cell selection transistor, and the second band defining the gate region of the floating gate transistor. A portion of the first band extends over a portion of insulating layer adjacent to the byte selection transistor. An opening is formed in the portion of the first band, exposing the first polysilicon layer, and a conductive layer is formed in the opening, electrically coupling the first polysilicon layer with the second polysilicon layer.

Process for manufacturing a byte selection transistor for a matrix of non volatile memory cells and corresponding structure

In a matrix of non volatile memory cells integrated on a semiconductor substrate, each memory cell includes a floating gate transistor and a selection transistor formed in a first active area, while each byte includes a byte selection transistor formed in a second active area separated from the first by portions of insulating layer. A portion of a multilayer structure including a gate oxide layer, a first polysilicon layer, a dielectric layer, and a second polysilicon layer extends over the byte selection and selection transistors, forming the gate regions thereof, and further extending on a portion of insulating layer. A conductive layer is formed in an opening in the second polysilicon and dielectric layers, over the portion of insulating layer, putting the first polysilicon layer in electric contact with the second polysilicon layer. Another portion of the multiplayer structure comprises the gate region of the floating gate transistor.

A method for manufacturing an integrated circuit having a memory device and a logic circuit includes forming a plurality of first transistors in a first portion of a semiconductor substrate, a plurality of second transistors in a second portion of the semiconductor substrate, and a plurality of memory cells in a third portion of the semiconductor substrate. A matrix mask used for selectively removing a dielectric layer from the first and third portions of the semiconductor substrate allows dielectric to remain on a floating gate of the plurality of memory cells and on the gate electrodes of the plurality of first transistors. A control gate is then formed on the floating gate, which is separated by the dielectric. Portions of the gate electrodes for the plurality of first transistors are left free so that contact is made with the transistors.

Method of manufacturing an integrated circuit, for integrating an electrically programmable, non-volatile memory and high-performance logic circuitry in the same semiconductor chip

A lateral DMOS transistor having a drain region which comprises a high-concentration portion with which the drain electrode is in contact and a low-concentration portion which is delimited by the channel region. In addition to the conventional source, drain, body and gate electrodes, the transistor has an additional electrode in contact with a point of the low-concentration portion of the drain region which is close to the channel. The additional electrode permits a direct measurement of the electric field in the gate dielectric and thus provides information which can be used both for characterizing the transistor and selecting its dimensions and for activating devices for protecting the transistor and/or other components of an integrated circuit containing the transistor.

Lateral DMOS transistor with first and second drain electrodes in respective contact with high-and low-concentration portions of a drain region

Method of manufacturing an electrically programmable, non-volatile memory and high-performance logic circuitry in the same semiconductor chip

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.

Growing community of inventors

Bernareggio, Italy

Elisabetta Palumbo