Evaluation of thermal balancing techniques in InGaP/GaAs HBT power arrays for wireless handset power amplifiers

Metzger, A.; d’Alessandro, V.; Rinaldi, N.; Zampardi, P.J.

doi:10.1016/j.microrel.2013.06.013

Cited by 12 publications

(8 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The third and last case study refers to 2 power GaAs HBT arrays exhibiting different thermal coupling between the individual devices, including both weak and tight coupling cases, as reported in Metzger et al The identification algorithm is applied to a [12×12] thermal impedance matrix, which has been fully calculated with the semianalytical method in Joy and Schlig, and resulting in single matrix elements spanning different order of magnitude. The identification with only 20 time constants show very accurate results for all the matrix elements, despite they range from 10 −1 to 10 −7 , as shown in Figures and .…”

Section: Algorithm Validation and Reference Case Studiesmentioning

confidence: 99%

Advancements in the identification of passive RC networks for compact modeling of thermal effects in electronic devices and systems

Tommasi

Magnani

Magistris

2017

Int J Numerical Modelling

View full text Add to dashboard Cite

We deal with the problem of identifying the parameters of an equivalent lumped RC multiport network from time domain tabulated data of a corresponding distributed real eigenvalues problem, as obtained from either measurements or accurate simulation tools. A novel step response matrix identification procedure is proposed, based on the combination of an outer nonlinear least squares iteration for the relocation of time constants, and an inner convex programming cycle for the identification of the corresponding residue matrix terms, able to guarantee a priori the passivity property of the equivalent RC network. The structure of the algorithm and its principal functions connections are shown, and the mathematical features of the proposed formulation of the identification problem are accurately described and commented. Moreover, the possibility of getting direct synthesis of a Foster generalized concretely passive multiport, as a consequence of the optimal identification of a passive real eigenvalues model from data, is discussed. Since the technique is well suited (although not limited) to the reduced analysis of typical electro‐thermal problems, a set of significant case studies in this area is considered. In this way the algorithm present implementation is validated, also comparing it to previous well assessed methods, evidencing its large potential and value.

show abstract

Section: Algorithm Validation and Reference Case Studiesmentioning

confidence: 99%

Advancements in the identification of passive RC networks for compact modeling of thermal effects in electronic devices and systems

Tommasi

Magnani

Magistris

2017

Int J Numerical Modelling

View full text Add to dashboard Cite

show abstract

“…The most common method to prevent this mechanism is to resort to a uniform distribution of base ballasting resistors; nevertheless, more recently it has been found that solutions relying on nonuniform layout of the individual HBTs and/or nonuniform base ballasting favor a more even temperature field over the array, thus further alleviating ET effects [15]. s 32nd IEEE SEMI-THERM Symposium The non-trivial task of identifying a proper thermal design of the PA output stage should in principle be supported by accurate ET simulation tools.…”

Section: Gaas Power Amplifiermentioning

confidence: 99%

“…In this Section, we apply the approach proposed in Section 3 by extracting the DCTM of the output stage of a wireless handset InGaP/GaAs PA fabricated by Skyworks and composed by 48 HBTs arranged in 4 rows [15]; each twoemitter HBTs was described with two IHSs shaped as rectangular parallelepipeds, thus leading to 96 IHSs. The thermal representation of the die is shown in Fig.…”

Section: Gaas Power Amplifiermentioning

confidence: 99%

Novel MOR approach for extracting dynamic compact thermal models with massive numbers of heat sources

Codecasa

Magnani

d’Alessandro

et al. 2016

2016 32nd Thermal Measurement, Modeling &Amp; Management Symposium (SEMI-THERM)

Self Cite

View full text Add to dashboard Cite

A novel Model Order Reduction approach for the construction of Dynamic Compact Thermal Models is presented. With respect to previous approaches, this methodology allows reducing the complexity of the constructed models, from quadratically to linearly dependent on the number of independent heat sources. In such a way, the approach allows constructing Dynamic Compact Thermal Models practically without limitations on the number of heat sources. The proposed methodology is validated through the application to two state-of-the-art electronic systems.

show abstract

“…Pervasive examples are the collapse of current gain affecting multi‐finger GaAs HBTs, which can be SOA‐limiting or even destructive, the discrepancy between dynamic and static error vector magnitude, thermal memory effects, and reliability/ruggedness issues in GaAs HBT PAs. Since the late 80s a plethora of papers have been published, which deal with the thermal or ET behavior of single‐ and multi‐finger transistors as well as of circuits in GaAs technology (representative ones being). Many studies focused on the metallization due to the important role played by the upward heat flow in this technology (the low thermal conductivity of the GaAs substrate mitigates the downward flow to the backside).…”

Section: Introductionmentioning

confidence: 99%

“…Most of them have proposed and/or investigated solutions based on thermal shunts . Other works dealing with multi‐finger transistors have promoted emitter or base ballasting and nonuniform finger spacing or length for assigned die and emitter areas . Some papers have also studied the beneficial effect of a thermally‐conductive and/or shorter path from the heat dissipation region to the sink, which can be obtained with flip‐chip packaging or alternative strategies based on thermal vias …”

Section: Introductionmentioning

confidence: 99%

Accurate and efficient analysis of the upward heat flow in InGaP/GaAs HBTs through an automated FEM‐based tool and Design of Experiments

d’Alessandro

Catalano

Codecasa

et al. 2018

Int J Numerical Modelling

View full text Add to dashboard Cite

This paper presents an extensive analysis aimed at quantifying the impact of all the key technology parameters on the upward heat flow in state-of-the-art InGaP/GaAs heterojunction bipolar transistors (HBTs) for various emitter areas and shapes. Extremely accurate thermal simulations are conducted in a relatively short time with a tool relying on a commercial 3-D finite-element method (FEM) solver and an in-house routine for automated geometry construction, optimized mesh generation, sequential solution, and data storing/processing. Design of Experiments is used to define a thermal resistance model as a function of the aforementioned parameters on the basis of a few FEM data. also studied the beneficial effect of a thermally-conductive and/or shorter path from the heat dissipation region to the sink, which can be obtained with flip-chip packaging 13,14,19,20,22,30 or alternative strategies based on thermal vias. 17,32 Unfortunately, almost all the thermal analyses presented in the above papers are (sometimes unacceptably) inaccurate: the real-and complex-device structures are always represented with simplified (or even oversimplified) domains to allow (1) the development of analytical models for the temperature distribution or (2) an easy construction/meshing of the 3-D geometry for numerical simulations; still now, in spite of the continuous improvement in PC performances, task (2) is not trivial if performed manually, especially when all technological details must be taken into account.Recently, the upward heat flow has been given attention in some works from the authors. [37][38][39][40] In particular, besides the metallization, the often overlooked role played by the emitter stack (previously investigated only in a study by Anholt 22 ) has been analyzed in a state-of-the-art InGaP/GaAs HBTs in previous papers [38][39][40] ; the relevance of these studies is driven by the low thermal conductivities of the ternary InGaAs and InGaP emitter layers (even lower than GaAs), which make thermal shunt solutions less effective. For this purpose, the authors have used a simulation/modeling strategy based on combining (1) a tool that relies on a 3-D finite-element method (FEM) software package aided by an in-house routine, and (2) Design of Experiments (DOE) to analytically derive a predictive thermal resistance model starting from a minimized number of FEM results. Contrary to prior work, the proposed tool ensures very high simulation accuracy: starting from the actual masks used for device fabrication, it allows an automated and extremely detailed construction/meshing of the 3-D transistor structure in the environment of the FEM solver. Thanks to this feature, it can be easily integrated into a standard design process, and can in principle be used for any device technology.This work aims at extending the analysis presented in Catalano et al 38 where the impact of emitter stack and metallization layers on the thermal behavior was evaluated for various emitter areas and shapes in single-finger InGaP/GaAs HBTs. Compared wi...

show abstract

Evaluation of thermal balancing techniques in InGaP/GaAs HBT power arrays for wireless handset power amplifiers

Cited by 12 publications

References 9 publications

Advancements in the identification of passive RC networks for compact modeling of thermal effects in electronic devices and systems

Advancements in the identification of passive RC networks for compact modeling of thermal effects in electronic devices and systems

Novel MOR approach for extracting dynamic compact thermal models with massive numbers of heat sources

Accurate and efficient analysis of the upward heat flow in InGaP/GaAs HBTs through an automated FEM‐based tool and Design of Experiments

Contact Info

Product

Resources

About