Effects of Synchrotron X-Ray Irradiation on Hot Carrier Reliability in Subquarter-Micrometer NMOSFETs

Mitsuru HARADA
Kimiyoshi DEGUCHI
Tadahito MATSUDA

IEICE TRANSACTIONS on Electronics   Vol.E76-C    No.4    pp.506-510
Publication Date: 1993/04/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section INVITED PAPER (Special Issue on Sub-Half Micron Si Device and Process Technologies)
Category: Device Technology
MOSFET,  reliability,  hot carrier,  synchrotron X-ray,  

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Hot carrier reliability due to residual damage in the gate oxide created by synchrotron X-ray irradiation is investigated for subquarter-micrometer NMOSFETs under a wide irradiation-dose range (103,000 mJ/cm2). Although irradiation-induced interface-traps and positive charges are completely eliminated after 400 post-metalization-annealing, neutral electron traps partially remain. The effects of the residual trapa on hot-carrier degradation can be negligible when gate oxides thinner than about 5 nm are used, and it is found that there is no effect of irradiation damage on interface-trap generation due to injected hot-carriers. It is concluded that the influence of synchrotron radiation X-ray lithography on hot-carrier-induced degradation in subquarter-micrometer NMOSFETs can be negligible.