Increase of parasitic resistance of shallow p+ extension with SiN sidewall process by hydrogen passivation of boron and its improvement by preamorphization for sub-0.25 mu m pMOSFETs

With decreasing implantation energy of BF sub(2) lower than 10 keV, anomalously low activation efficiency as low as 15% in p+ source/drain extension of pMOSFETs is observed when SiN gate sidewalls are used. It is demonstrated that hydrogen from the SiN film diffuses into the p+ extension, and passiv...

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Main Authors: Inaba, S, Murakoshi, A, Tanaka, M, Takagi, M T, Koyama, H, Koike, H, Yoshimura, H, Matsuoka, F
Format: Conference Proceeding
Language:English
Online Access:Get full text
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Summary:With decreasing implantation energy of BF sub(2) lower than 10 keV, anomalously low activation efficiency as low as 15% in p+ source/drain extension of pMOSFETs is observed when SiN gate sidewalls are used. It is demonstrated that hydrogen from the SiN film diffuses into the p+ extension, and passivates boron acceptor. Significant decrease of activation efficiency with reducing BF sub(2) implantation energy indicates that decrease of amorphization rate at the extension implantation is the origin of low activation efficiency. In sub-0.25 mu m era, the extra amorphization step is indispensable to suppress hydrogen passivation of boron for achieving low parasitic resistance of pMOSFETs.
ISSN:0743-1562