Gate oxide thinning at the active device/FOX boundary in submicrometer PBL isolation

Author

Kamgar, Avid ; Hillenius, S.J. ; Baker, R. Michael ; Nakahara, S. ; Bechtold, Philip F.

Author_Institution

AT&T Bell Labs., Murray Hill, NJ, USA

Volume

42

Issue

12

fYear

1995

fDate

12/1/1995 12:00:00 AM

Firstpage

2089

Lastpage

2095

Abstract

The impact of several poly buffer LOCOS processing parameters on the integrity and defect density (yield) of the gate oxide has been investigated by correlating electrical and structural studies. We found that a thin PBL pad-oxide, in general, gives rise to higher defect density. In addition, it results in a sharp active device/field oxide (FOX) boundary which, by the process of screen oxide growth and etch-back and FOX pull-back, creates a step in the Si in the bird´s beak region. TEM studies revealed gate oxide thinning by as much as 30% over this step, explaining the early gate oxide breakdown at the active device/FOX region

Keywords

MOS capacitors; etching; isolation technology; oxidation; scanning electron microscopy; transmission electron microscopy; 0.35 mum; FOX pull-back; NOVLAP capacitors; OVLAP capacitors; PBL pad-oxide; SEM; Si; Si-SiO₂; TEM studies; active device/FOX boundary; bird´s beak region; defect density; etch-back; gate oxide breakdown; gate oxide integrity; gate oxide thinning; gate oxide yield; poly buffer LOCOS processing parameters; screen oxide growth; structural analysis; submicrometer PBL isolation; Amorphous materials; Buffer layers; Electric breakdown; Etching; Isolation technology; Lithography; Oxidation; Silicon; Tensile stress; Testing;

fLanguage

English

Journal_Title

Electron Devices, IEEE Transactions on

Publisher

ieee

ISSN

0018-9383

Type

jour

DOI

10.1109/16.477765

Filename

477765