Size dependent influence of the pad and gate parasitic elements to the microwave and noise performance of the 0.35 µm n and p type MOSFETs.

Noise and s-parameters of the p and n type MOSFETs were measured and simulated for the different bias points. The pad parasitic models of the „short“ and „open“ were extracted by means of comparison of measured and simulated s-parameters. The influence of the pad elements on the microwave noise was analyzed. The simulation of intrinsic device noise was performed on the basis of good fit of measured and simulated noise and s-parameters of the DUT. For the narrow gate (50 µm) width devices the pad parasitics significantly affect microwave noise performance for both p and n type devices. At the lower drain currents the kinks and loops in the s-parameters were observed. At low drain current a resonant peak in NFmin and Rn around 8 GHz was found. Those resonant effects observed in noise and s-parameters diminish with the increase of the drain current and were qualitatively accounted for by the simulations by using equivalent circuit with the parasitic inductive element coupled to the gate

mm-Wave noise modeling in advanced SiGe and InP HBTs

DC, RF and noise characteristics of advanced InP/InGaAs and Si/SiGe heterojunction bipolar transistors (HBTs) were measured and modeled in a broad frequency range. Equations for systematically modeled correlated noise in bipolar transistors and their implementation in the compact models HICUM/L0 and L2 are proposed. The models are verified for advanced SiGe HBTs up to 300 GHz by hydrodynamic device simulation and by results from the Boltzmann transport equation. The verified model was used for analyzing the noise of advanced InP/InGaAs and Si/SiGe HBTs. Compared to Si/SiGe HBTs a higher noise at lower frequencies was observed in InP/InGaAs HBTs due to a higher base recombination current. InP HBTs shows a good noise performance beyond 100 GHz and due to their better product can compete with advanced Si/SiGe HBTs for LNA design at mm-wave frequencies

Harmonic Distortion Analysis of InP HBTs with 650 GHz f(max) for High Data Rate Communication Systems

High frequency (h.f.) harmonic distortion (HD) of advanced InP heterojunction bipolar transistors (HBTs) with various emitter widths was investigated. Geometry scalable parameters for the compact model (CM) HICUM/L2 v. 2.34, featuring a two-region base-collector capacitance formulation, were extracted from temperature dependent DC and AC measurements of HBTs and from the special test structures. Single tone harmonic distortion and active two tone load pull measurements were carried out for different emitter area devices. The compact model was used for data analysis

Nonlinear transport and fluctuation characteristics of doped semiconductors

Fluctuation phenomena in doped n-type GaAs, at moderate applied electric fields being influenced by interelectron scattering, are interpreted in terms of effective electron temperature. Electron Fick’s diffusion coefficients in longitudinal and transfer direction are estimated

Microwave Noise Analysis in InP and GaAs HBTs

High frequency (h.f.) noise characteristics of advanced InP and GaAs HBTs were measured and simulated. The compact model (CM) HICUM/L2 v2.34 was used for the DC, AC and noise simulation as well as for the noise analysis. Geometry scalable model parameters for InP HBTs with the different emitter widths and lengths were extracted from temperature dependent DC and AC measurements on HBTs and special test structures. The CM is in good agreement with measured data. Non-equilibrium electron transport was found to shape fT and fmax for GaAs HBTs. For both HBT types, based on the noise source decomposition, an analysis of the influence of the different noise sources on the minimum noise figure (NFmin) was performed at different base-collector biases VBC. It was found that noise due to intervalley transfer related electron scattering has negligible impact on NFmin for both InP and GaAs HBTs. H.f. noise reduction as a result of Coulomb current blocking in GaAs HBTs was confirmed. Shot noise correlation was investigated in GaAs HBTs with different base layer thickness (wB) and base doping for the optimal h.f. noise behavior

Experimental evidence of MOSFET high frequency noise reduction by channel engineering

In this paper, measured RF noise performance of graded-channel metal–oxide–semiconductor (MOS) transistors (GCMOS—also named laterally asymmetric channel transistors) shows impressive reduction in minimum noise figure (NFmin) as compared to classical MOSFET transistors (with the same gate length Lg = 0.5 μm). The reason is proven to be because of the higher noise correlation coefficient (C). GCMOS also shows lower sensitivity to extrinsic thermal noise as compared to classical MOSFET. Moreover, it is demonstrated that the use of 0.5-μm-gate-length GCMOS gives a competitive RF noise performance as compared to 0.25-μm-gate-length classical nMOS transistors