Increasing Importance of Electronic Thermal Noise in Sub-0.1 µm Si-MOSFETs

Nobuyuki SANO  

IEICE TRANSACTIONS on Electronics   Vol.E83-C   No.8   pp.1203-1211
Publication Date: 2000/08/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: INVITED PAPER (Special Issue on 1999 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD'99))
Category: Device Modeling and Simulation
Monte Carlo simulation,  current fluctuation,  thermal noise,  shot noise,  central limit theorem,  

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We investigate the intrinsic current fluctuations in small Si-MOSFETs via the Monte Carlo device simulation. It is demonstrated that the temporal fluctuation of the drain current in Si-MOSFETs attains a significant fraction of the averaged drain current when the device width is scaled down to the deep sub-µm regime. This is caused by the drastic decrease in the number of channel electrons. This finding holds true whenever the device width is reduced to deep sub-µm, regardless of the channel length. Most importantly, current fluctuation is associated with the quasi-equilibrium thermal noise in the heavily-doped source and drain regions, whereas its magnitude with respect to the averaged drain current is directly related to the number of channel electrons underneath the gate.