Hot spot analysis in integrated circuit substrates by laser mirage effect

3 páginas, 2 figuras.This work shows an analytical and experimental technique for characterizing radial heat flow present in integrated circuits (ICs) when power is dissipated by integrated devices. The analytical model comes from the resolution of the Fermat equation for the trajectory of rays and supposing a spherical heat source dissipating a time-periodic power. An application example is presented; hence demonstrating how hot spots and heat transfer phenomena in the IC substrate can be characterized. The developed method may become a practical alternative to usual off-chip techniques for inspecting hot spots in ICs and to experimentally characterize heat flow in the semiconductor substrate.This work has been partially supported by the Consejo Superior de Investigaciones Científicas (CSIC) (under contract “Junta para la Ampliación de Estudios,” JAEDoc No. E-08–2008–0637732) and the Spanish Ministry of Science and Innovation (research programs THERMOS TEC2008- 05577, RUE CSD2009-00046, TERASYSTEMS TEC2008- 01856, and Ramón y Cajal RYC-2010-07434).Peer reviewe

Reduced-Order Thermal Behavioral Model Based on Diffusive Representation

14 páginas, 15 figuras, 2 tablas.-- et al.The virtual prototyping of power electronic converters requires electrothermal models with various abstraction levels and easy identification. Numerous methods for the construction of compact thermal models have been presented in this paper. Few of them propose state-space models, where the model order can be controlled according to the necessity of the virtual prototyping analyses. Moreover, the model reduction methods require the experience of the engineer and previous calibration. Diffusive representation (DR) is proposed here as an original and efficient method to build compact thermal models as state-space models. The model reduction is obtained through the model parameter identification and/or the time horizon of the measurement data provided for the identification. Instead of eigenvalue elimination, the method enables to specify adequately inside the model the frequency domain wished for the virtual analysis at hand. The proposed method is particularly dedicated to the system optimization phases. Experimental and simulation results are in good agreement. The advantages and limitations of the DR are discussed in comparison to published methods.Peer reviewe

Prikaz stanja silicijevih MOS upravljanih učinskih sklopova i PiN ispravljača

Revolutionary advances and developments have been made in power semiconductor device technologies during the last decades which have allowed the improvement of power electronic systems in terms of their efficiency and reliability. The advent of MOS-gated power switches such as the power MOSFET and the IGBT showing high input impedance has been a real breakthrough in the design and fabrication of power electronic systems. This paper reviews the recent progress in the development of Si MOS-gated power devices and rectifiers. The evolution of these devices’ technologies together with the introduction of revolutionary device concepts is also discussed. Concretely, the introduction of trench technologies for power MOSFETs and the use of the super-junction concept for breaking the 1D-silicon limit are highlighted. Developments in IGBTs such as those based on the use of thin wafers and strategies for optimising the plasma distribution in PT IGBTs during the on-state are also addressed. Finally, advances in PiN diode technologies including new concepts for both the anode and the cathode structures are also reviewed. These approaches have allowed the reduction of the PiN total losses and a soft reverse recovery behaviour, leading to a more rugged device.U posljednjim desetljećima svjedočimo razvoju sustava učinske elektronike u pogledu povećanja efikasnosti i pouzdanosti. Napredak je omogućen zahvaljujući izvanrednom napredku koji je postignut na području učinskih poluvodiča. Pojava MOS upravljanih učinskih sklopova s visokom ulaznom impedancijom, kao što su MOSFET i IGBT, rezultirao je probojem u projektiranju i proizvodnji sustava učinske elekronike. Ovaj članak daje uvid u napredak koji je u posljednje vrijeme ostvaren u razvoju silicijeve MOS upravljane učinske elektronike i ispravljača. Uz dosadašnji razvoj tehnologije navedenih komponenata, u članku je uključen i osvrt na revolucionarne koncepte budućeg razvoja. Konkretno, u radu su objašnjene tehnologija rova za MOSFET i korištenje koncepta super spoja za probijanje granice jednodimenzionalnog silicija. Razmatrana su i poboljšanja IGBT-ova koja se baziraju na uporabi tankih pločica a strategijama optimiranja distribucije plazme u PT IGBT-ovima za vrijeme aktivnog stanja. Konačno, prikazan je i napredak u tehnologiji PiN dioda koji uključuje nove strukturalne koncepte katode i anode. Ovi pristupi su omogućili smanjenje ukupnih gubitaka PiN diode i blagu dinamiku reverznog oporavka, što rezultira povećanjem robusnosti sklopa

Development of an analog processing circuit for IR-radiation power and noncontact position measurements

6 páginas, 9 figuras, 1 tabla.An analog circuit which simultaneously performs radiation power and position measurement of an IR-laser spot (wavelength 1.3 μm) on a four quadrant photodiode is presented and described. Its main features are 2 MHz-bandwidth and low noise (14 mV rms) for a nominal working radiation power of 2 mW. This circuit has been implemented for the detection stage of an internal IR-laser deflection set-up, used to measure internal temperature gradients and free carrier concentration in vertical power devices. The measurements of the previously mentioned magnitudes inside the drift region of a 600 V PT-IGBT are presented under critical operation conditions. This circuit, however, can also be used in other noncontact position and power radiation detection systems that require a high bandwidth and low noise levels. Moreover, the different noise sources along the detecting system have been identified. It is shown that the main contribution to the noise level at the processing circuit output is basically introduced by its second stage (analog divisor), assuring, for a 1 mm laser spot centered at the photodetector, a maximum resolution in position measurement below 2 μm.This work was partially supported by the CICYT, Project No. TIC 2000-1403-C003-03 and by the EC Growth Project ATHIS sG1RD-CT-2002-00729d.Peer reviewe

Heat power source controller circuit

3 páginas.Experimental works on thermal management of electronic systems, such as thermal resistance or thermal conductivity measurement, often require a controlled heat power source. This article proposes a circuit based on an integral automatic controller that sets a heat power dissipation level of a power metal-oxide-semiconductor field effect transistor used as a heating device. It can operate in dc mode, setting a steady power generation, and in pulsed mode, controlling a transient power wave form. The controller operation principle is established together with all details for its implementation and use.This work was partially supported by the EC Growth Project ATHIS (G1RD-CT-2002-00729).Peer reviewe

Reduced-Order Thermal Behavioral Model Based on Diffusive Representation

14 páginas, 15 figuras, 2 tablas.-- et al.The virtual prototyping of power electronic converters requires electrothermal models with various abstraction levels and easy identification. Numerous methods for the construction of compact thermal models have been presented in this paper. Few of them propose state-space models, where the model order can be controlled according to the necessity of the virtual prototyping analyses. Moreover, the model reduction methods require the experience of the engineer and previous calibration. Diffusive representation (DR) is proposed here as an original and efficient method to build compact thermal models as state-space models. The model reduction is obtained through the model parameter identification and/or the time horizon of the measurement data provided for the identification. Instead of eigenvalue elimination, the method enables to specify adequately inside the model the frequency domain wished for the virtual analysis at hand. The proposed method is particularly dedicated to the system optimization phases. Experimental and simulation results are in good agreement. The advantages and limitations of the DR are discussed in comparison to published methods.Peer reviewe

Analysis of Excess Carrier Concentration Control in Fast-Recovery High Power Bipolar Diodes at Low Current Densities

10 páginas, 10 figuras, 3 tablas.The combination of emitter control with local lifetime tailoring by ion irradiation is experimentally analyzed in fast-recovery high power diodes. For this purpose, the carrier lifetime and excess carrier concentration profiles are measured and modeled within the low doped region of unirradiated and helium irradiated diodes under low current densities (<20 A/cm2). The interest in working under these current conditions responds to the fact that the only recombination mechanism that modulates the steady-state carrier concentration is that of the multiphonon-assisted case (Shockley–Read–Hall model). This enables us to extract parameters for their modeling under arbitrary working conditions and to detect the influence of ion irradiation on the excess carrier distribution. For a better comprehension of the results, the excess carrier profile in the unirradiated diode is physically analyzed in detail by an analytical model. Afterward, physical simulations are also carried out, employing the experimental lifetime profiles as input parameters. As a result, a very good agreement between simulation predictions and experiments is observed, which is used to explain, by the support of analytical expressions, how the ion-irradiation process can improve the diode operation at low current densities during the late phase of the reverse recovery.This work has been partially supported by the “Consejo Superior de Investigaciones Científicas” (CSIC) (under contract “Junta para la Ampliación de Estudios,” JAE-Doc), the Spanish Ministry of Science and Innovation (research programs: THERMOS TEC2008- 05577 and RUE CSD2009-00046), and the Ministry of Education, Youth and Sports of the Czech Republic (research program no. MSM 6840770017).Peer reviewe