Federica Cappelluti

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We propose a rigorous finite-element-method (FEM) model for traveling-wave structures on doped semiconductor substrates based on a full-wave electromagnetic model coupled to a drift-diffusion description of carrier transport. The coupled model allows to describe field-carrier interactions in distributed structures, where strong low-frequency dispersion due(More)
The paper presents the results of the application of physics-based mixed-mode simulations to the analysis and optimization of the reverse recovery for Si-based fast recovery diodes (FREDs) using Platinum (Pt) lifetime killing. The trap model parameters are extracted from Deep Level Transient Spectroscopy (DLTS) characterization. The model is validated(More)
A physics-based model for PiN power diodes is developed and implemented as a SPICE subcircuit. The model is based on a distributed equivalent circuit representation of the PiN base region, which is obtained by solving the ambipolar diffusion equation with the finite difference method. The model is validated against experimental characterization that is(More)
This paper presents an accurate and flexible approach to the self-consistent electrothermal modeling of III-N-based HEMTs, combining a temperature-dependent electrical compact model with a novel behavioral nonlinear dynamic thermal model, suitable for circuit-level simulations. The behavioral thermal model is extracted, according to a Wiener-like approach,(More)
This paper presents a rigorous numerical approach to the stability analysis of multi-device power amplifiers. As well known, amplifiers exploiting symmetrical power dividing and combining networks exhibit both even-mode and odd-mode instabilities, the latter being impossible to detect in a input-output port small-signal stability assessment. In the present(More)
We present a novel analysis of thermal instabilities and oscillations in multifinger heterojunction bipolar transistors (HBTs), based on a harmonic-balance computer-aided-design (CAD)-oriented approach to the dynamic stability assessment. The stability analysis is carried out in time-periodic dynamic conditions by calculating the Floquet multipliers of the(More)
The paper presents a comprehensive analysis of the large-signal stability of symmetric multibranch power amplifiers through the application of Floquet theory implemented directly in the frequency domain. The generality of the approach allows to gain a global assessment of the amplifier stability, without resorting to specific approaches based on layout(More)
A new self-consistent dynamic electro-thermal model for power HBTs is presented coupling a circuit-oriented electrical model, fitted on experimental data, with a full frequency domain thermal model. The thermal model provides the exact frequency behaviour of the device thermal impedance through a quasi-3D approach. The electro-thermal self-consistent(More)
Thanks to its wide bandgap, exceptionally high thermal conductivity and relatively high carrier velocities, diamond exhibits attractive semiconductor properties that make it an interesting candidate for high power, high frequency and high temperature solid-state microelectronic devices, able to withstand harsh environmental conditions (in terms of(More)
The physical operation, crystal growth, optical lithography and electron-beam lithography fabrication and measured performance of single-crystal diamond active devices for microwave frequencies are presented. Preliminary results suggest the potentials of such technology in high-frequency and power operation. The use in space applications is envisaged,(More)