Stmicroelectronics S.r.l.

Daniele Zompi

Nicolas Demange

Paola Zuliani

Enrico Castaldo

Elisabetta Palumbo

Roberto Annunziata

Alberto Jose' Di Martino

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 biasing structure for a memory cell storage element, for setting an operating voltage at an accession electrode of the memory cell storage element. The biasing structure includes a biasing transistor coupled to the accession electrode and adapted to set the operating voltage based on a biasing voltage received at a control electrode of the biasing transistor, and a biasing voltage generator for generating the biasing voltage. The biasing voltage generator includes a feedback voltage regulation structure adapted track changes in a threshold voltage of the biasing transistor, so as to keep the operating voltage at the accession electrode of the memory cell storage element substantially stable against operating condition changes.

Biasing structure for accessing semiconductor memory cell storage elements

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Misterbianco, Italy

Daniele Zompi