Analytical and Numerical Study of the Impact of Halos on Surrounding-Gate MOSFETs

Zunchao LI  Ruizhi ZHANG  Feng LIANG  Zhiyong YANG  

IEICE TRANSACTIONS on Electronics   Vol.E92-C   No.4   pp.558-563
Publication Date: 2009/04/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E92.C.558
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Semiconductor Materials and Devices
MOSFET,  surrounding-gate,  compact model,  halo,  

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Halo doping profile is used in nanoscale surrounding-gate MOSFETs to suppress short channel effect and improve current driving capability. Analytical surface potential and threshold voltage models are derived based on the analytical solution of Poisson's equation for the fully depleted symmetric and asymmetric halo-doped MOSFETs. The validity of the analytical models is verified using 3D numerical simulation. The performance of the halo-doped MOSFETs are studied and compared with the uniformly doped surrounding-gate MOSFETs. It is shown that the halo-doped channel can suppress threshold voltage roll-off and drain-induced barrier lowering, and improve carrier transport efficiency. The asymmetric halo structure is better in suppressing hot carrier effect than the symmetric halo structure.