Microsc. Microanal. Microstruct. 1, 215-231 (1990)
DOI: 10.1051/mmm:0199000103021500

3D statistics from TEM observations of TPFG EEPROM memory cells

Paolo Mengucci¹, Daniele Rinaldi¹, Stefano Santini² et Massimo Vanzi<sup>3

1</sup>  Dipartimento di Scienze dei Materiali e della Terra, Università di Ancona, via Brecce Bianche, 60131 Ancona, Italy
²  Istituto di Fisica e Bioingegneria, Università di Urbino, via S. Chiara, 61029 Urbino, Italy
³  Telettra S.p.A., Q& R, via Capo di Lucca 31, 40126 Bologna, Italy

Abstract
Commercial EEPROM devices based on Textured Polysilicon Floating Gate (TPFG) technology were observed by TEM in cross-sectional view. At the polysilicon surfaces where electron tunneling takes place during the WRITE/ERASE cycle many tips where detected, as expected. A statistical model correlating the observed 2D tip distribution with the relevant 3D distribution is proposed.

Résumé
Des dispositifs commerciaux EEPROM fabriqués selon la technologie TPFG (textured polysilicon floating gate) ont été observés en coupe par microscopie électronique à transmission. Comme prévu, de nombreuses pointes sont visibles sur la surface du silicium polycristallin où l'émission tunnel d'électrons se produit lors du cycle ECRITURE/EFFACEMENT. On propose un modèle statistique reliant les distributions 2D observées de pointes avec la distribution 3D réelle.

PACS
8570 - Magnetic devices.

Key words
EEPROM memory -- TEM -- Cross section(geometry) -- Statistical models -- Experimental study


© EDP Sciences 1990