Subquarter-Micrometer PMOSFET's with 50-nm Source and Drain Formed by Rapid Vapor-Phase Doping (RVD)

Yukihiro KIYOTA  Tohru NAKAMURA  Taroh INADA  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E77-C   No.3   pp.362-366
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: Device Technology
Keyword: 
PMOSFET,  RVD,  shallow-junction,  

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Summary: 
Single-drain PMOSFET's with a very shallow source and drain were fabricated using a new doping method called rapid vapor-phase doping (RVD). This process is carried out in hydrogen atmosphere using B2H6 as a source gas. By varying flow rate of B2H6 and the doping time, shallow boron doped layers which are suitable for source and drain regions of MOSFET's are formed. The fabricated RVD-PMOSFET's have 50-nm source and drain regions with peak concentration of 41020 cm-3 which were formed under the condition of 800, B2H6 flow rate of 50 ml/min. The junction depth was one third of those formed by conventional low-energy BF2 ion implantation. RVD-PMOSFET's showed normal operation down to poly-Si gate length Lg of 0.18 µm. The advantage of shallow junction was clearly shown by the threshold voltage roll-off characteristics, that is, it was suppressed down to 0.18 µm, whereas in conventional device, roll-off occurred below 0.6 µm. This better short channel behavior suggests that RVD forms shallow source and drain regions with weaker lateral diffusion. This result confirms that RVD is an effective method for forming shallow junctions for MOSFET's.