Solid-State Electronics, Vol.73, 64-73, 2012
RF dynamic and noise performance of Metallic Source/Drain SOI n-MOSFETs
This paper presents a detailed study of the RF and noise performance of n-type Schottky barrier (SB) MOSFETs with a particular focus on the influence of the Schottky barrier height (SBH) on the main dynamic and noise figures of merit. With this aim, a 2D Monte Carlo simulator including tunnelling transport across Schottky interfaces has been developed, with special care to consider quantum transmission coefficients and the influence of image charge effects at the Schottky junctions. Particular attention is paid to the microscopic transport features, including carrier mean free paths or number of scattering events along the channel for investigating the optimization of the device topology and the strategic concepts related to the noise performance of this new architecture. A more effective control of the gate electrode over drain current for low SBH (discussed in terms of internal physical quantities) is translated into an enhanced transconductance g(m) cut-off frequency f(T), and non-quasistatic dynamic parameters. The drain and gate intrinsic noise sources show a noteworthy degradation with the SBH reduction due to the increased current, influence of hot carriers and reduced number of phonon scatterings. However, the results evidence that this effect is counterbalanced by the extremely improved dynamic performance in terms of g(m) and f(r). Therefore, the deterioration of the intrinsic noise performance of the SB-MOSFET has no significant impact on high-frequency noise FoMs as NFmin R-n and G(ass) for low SBH and large gate overdrive conditions. The role of the SBH on Gamma(opt), optimum noise reactance and susceptance has been also analyzed. (C) 2012 Elsevier Ltd. All rights reserved.
Keywords:Schottky barrier (SB) MOSFET;Silicon-on-insulator (SOI);Monte Carlo modelling;Intrinsic noise sources;Minimum noise figure (NFmin);RF performance