Resolving the mechanisms of current gain increase under forward current stress in poly emitter n-p-n transistors

Author

Zhao, J. ; Li, G.P. ; Liao, K.Y. ; Chin, Maw-Rong ; Sun, Jack Y C ; La Duca, A.

Author_Institution

Dept. of Electr. & Comput. Eng., California Univ., Irvine, CA, USA

Volume

14

Issue

5

fYear

1993

fDate

5/1/1993 12:00:00 AM

Firstpage

252

Lastpage

255

Abstract

The mechanisms behind moderate bias current gain ( beta ) increase of n-p-n transistors under forward current stress are investigated in polysilicon emitter transistors processed with different dopant impurities and concentrations, and with different amounts of hydrogen plasma treatment. The results suggest that transport of atomic hydrogen toward the poly/monosilicon interface region and its subsequent passivation of dangling bonds at both poly grain boundaries and the poly/monosilicon interface are responsible for the moderate bias beta increase. To alleviate the beta instability, elimination of hydrogen involvement and/or a higher doping concentration inside the poly emitter in the back-end-of-line (BEOL) processes are/is recommended.<>

Keywords

bipolar transistors; dangling bonds; doping profiles; elemental semiconductors; passivation; silicon; H/sub 2/ plasma treatment; back end of line processes; current gain increase; dangling bond passivation; dopant concentration; dopant impurities; forward current stress; poly emitter n-p-n transistors; poly grain boundaries; polysilicon Si interface region; Aircraft; Contact resistance; Current density; Degradation; Grain boundaries; Hydrogen; Impurities; Leakage current; Passivation; Stress;

fLanguage

English

Journal_Title

Electron Device Letters, IEEE

Publisher

ieee

ISSN

0741-3106

Type

jour

DOI

10.1109/55.215184

Filename

215184