Noise Analysis of GaAs-MESFETs by Physics-Based Circuit Simulator Employing Monte Carlo Technique

Masahiro NAKAYAMA  Shinichi NARITA  Hiroki I. FUJISHIRO  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E88-C   No.7   pp.1509-1515
Publication Date: 2005/07/01
Online ISSN: 
DOI: 10.1093/ietele/e88-c.7.1509
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Microwaves, Millimeter-Waves
Keyword: 
Monte Carlo,  GaAs,  MESFET,  noise figure,  noise generation,  electron velocity,  

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Summary: 
Noise characteristics of GaAs metal-semiconductor field effect transistors (GaAs-MESFETs) with scaled-down dimensions are analyzed and modeled using a physics-based circuit simulator employing the Monte Carlo (MC) particle technique. The microscopic dynamics of electrons is also analyzed to investigate the mechanism of noise generation in a channel. Noise spectral densities of GaAs-MESFETs with two different geometries are estimated by evaluating fluctuations in instantaneous terminal currents. Then, minimum noise figures, F min, and noise figure circles are estimated using the noise spectral densities and Y-parameters. Because of an increase in y21 and suppression of an increase of noise spectral density, the device with an n+-region extending to below the drain-side edge of the gate contact exhibits a smaller noise figure. Suppression of the electron velocity fluctuation caused by electron transitions to higher valleys in a high electric field region is responsible for the noise suppression.