Elimination of Negative Charge-Up during High Current Ion Implantation

Kazunobu MAMENO  Atsuhiro NISHIDA  Hideharu NAGASAWA  Hideaki FUJIWARA  Koji SUZUKI  Kiyoshi YONEDA  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E77-C    No.3    pp.459-463
Publication Date: 1994/03/25
Online ISSN: 
DOI: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Quarter Micron Si Device and Process Technologies)
Category: Process Technology
Keyword: 
ion implantation,  charge-up,  electron shower,  oxide,  dielectric breakdown,  

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Summary: 
The dielectric breakdown characteristics of a thin gate oxide during high-current ion implantation with an electron shower have been investigated by controlling the energy distribution of the electrons. Degradation of the oxide has also been discussed with regard to the total charge injected into the oxide during ion implantation in comparison with that of the TDDB (time dependent dielectric breakdown). Experimental results show that the high-energy and high-density electrons which concentrated in the circumference of the ion beam due to the space charge effect cause the degradation of the thin oxide. It was confirmed that eliminating the high-energy electrons by applying magnetic and electric fields lowers the electron energy at the wafer surface, thereby effectively suppressing the negative charge-up.