1,721,005 research outputs found
Linking X Parameters to Physical Simulations for Design-Oriented Large-Signal Device Variability Modeling
Full text linkWe propose various techniques extending X parameters to include the effect of active microwave device variability by exploiting TCAD simulations. We discuss two possible implementations into Agilent ADS. Both approaches are validated against full microwave amplifier TCAD simulations
TCAD analysis of FinFET temperature-dependent variability for analog applications
No full textThe Green’s Function based TCAD device variability analysis is extended to allow for temperature-dependent variability, with negligible overhead in terms of simulation time with respect to fixed temperature simulations. We provide temperature and bias-dependent 3D variability analysis of the DC current for a FinFET structure from the 22 nm node, showing how to predict and mitigate the effects of poor thermal management. Based on the quasi-stationary assumption, preliminary analysis of self-heating effects of a FinFET medium power amplifier is also presented
Multibias TCAD Analysis of Trap Dynamics in GaN HEMTs
Full text linkIn this paper we exploit numerically efficient physical simulations to investigate the link between GaN HEMT low-frequency dispersion and the concentration of Fe induced buffer traps. We demonstrate that the sensitivity of the AC output conductance to trap concentration shows markedly different behavior according to the bias point, either in saturation or in the linear region at the HEMT knee voltage. The frequency dependency and the sensitivity of AC parameters in multiple bias points yield a deeper understanding of trap behavior and allow for easier identification of buffer trap signature in characterization data
TCAD analysis of GaN HEMT AC parameters through accurate solution of trap rate equations
Full text linkPhysics-based simulations allow for an accurate insight into the impact of trap dynamics on GaN HEMT performance. In particular, traps are responsible for the low-frequency dispersion of AC performance, e.g. the Y parameters. In this paper we present an in-house TCAD simulator implementing the trap rate equations coupled to the drift-diffusion physical model and solved through the Harmonic Balance algorithm. The developed TCAD allows for the extraction of the trap rate equations Green’s Functions (GFs) in the frequency domain. GFs are then used to compute the sensitivity of the AC Y parameters towards variations of the trap physical parameters (e.g. the trap energy) and to extract the local sensitivity, showing the parts of the device where traps influence most the HEMT AC parameters
TCAD simulation of microwave circuits: The Doherty amplifier
Full text linkPower amplifiers (PAs) for next generation of communication systems are expected to operate at higher frequency and bandwidth to support the growing data rates. The Doherty Power Amplifier (DPA) is one of the most promising circuits for the development of high efficiency PAs: its inherent structure, exploiting two interacting active devices, requires a nonlinear mixed-mode TCAD analysis with multiple devices. In this work we present for the first time a complete TCAD simulation of a DPA, exploiting an improved version of our in-house Harmonic-Balance based drift-diffusion simulator for large-signal mixed-mode analysis. We thus demonstrate that TCAD simulations are mature to assist the design of complex stages requiring multi-device large-signal analysis
Comments on "noise source modeling for cyclostationary noise analysis in large-signal device operation" (multiple letters)
No full textEfficient spectral domain technique for the frequency locking analysis of nonlinear oscillators
Full text linkAfter discussing an implementation of the harmonic balance technique that enables the efficient determination of the limit cycles for a nonlinear autonomous dynamical system, we consider the frequency locking of a set of oscillators that is studied by means of a proper extension of the aforementioned approach. Harmonic balance is also used for the numerical computation of the Floquet exponents and eigenvectors of the frequency locked limit cycle, thus enabling the assessment of its stability properties. The proposed technique is applied to the study of the frequency locking properties of a set of coupled Chua’s oscillators as a function of several parameters
Efficient TCAD Temperature-dependent Large-Signal Simulation of a FinFET Power Amplifier
Full text linkWe show a complete temperature-dependent analysis of a low power FinFET-based class A amplifier for small-cell applications based on an efficient approach to the temperature-dependent physics-based analysis of electron devices in Large Signal (LS) nonlinear conditions. The method extends the Green’s Function (GF) approach, already developed for the device LS noise and technological sensitivity, to calculate the LS device response to the temperature variation from a nominal, “cold” condition with a negligible numerical overhead with respect to the other GF-based analyses. T-dependent TCAD simulations are applied to assess the robustness of the FinFET-based power amplifier against device heating and load variations. Temperature variations dominate over load sensitivity, showing more than 1 dB output power loss and a PAE reduction from 28% to 23%. The proposed approach represents a first step towards the development of physically sound, temperature dependent, LS circuit models of nonlinear stages
TCAD-based Dynamic Thermal X-parameters for PA Self-Heating Analysis
Full text linkTCAD simulations are used to extract an accurate temperature-dependent X-parameter active device model, which describes it as instantaneously dependent on the junction temperature, and hence represents the ideal framework to analyze device self-heating. Once exported from TCAD into EDA tools, X-parameters are coupled to a dynamic thermal impedance, leading to a compact and efficient device black-box model, allowing for circuit-level analysis of thermal memory effects in microwave circuits, like Power Amplifiers (PAs), even in presence of complex modulated-signal excitation. In particular, we focus on the thermal analysis of a class-A PA at E-band based on a 54 nm Si FinFET. The accuracy of the temperature-dependent X-parameter model is demonstrated first by comparing circuit simulations with TCAD results in continuous wave. Then we extend the analysis to pulsed modulated operation, highlighting thermal dynamic effects as a function of the pulse period
- …
