Lidé

Ing. Vít Záhlava, CSc.

Všechny publikace

Effective Component Selection Method

  • DOI: 10.1109/ASDAM.2018.8544649
  • Odkaz: https://doi.org/10.1109/ASDAM.2018.8544649
  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    This article deals with minimizing errors caused by selection of passive components from production preferred values. For example, the E24 series of passive components only has 24 values per a decade, so the exact calculated value of the components must be rounded to the nearest value in the series. This rounding to an inaccurate value creates the error. The article describes several methods of minimizing this error and introduces a new method called “Effective Component Selection Method” that eliminates disadvantages of the previous methods. The principle is to select the components in such a way that the errors caused by the rounding of the individual circuit components cancel each other out in the resulting function of the circuit. This is achieved by optimization and by using the circuit’s degrees of freedom that are independent on its required function.

Operation of 4H-SiC high voltage normally-OFF V-JFET in radiation hard conditions: Simulations and experiment

  • DOI: 10.1016/j.microrel.2017.05.015
  • Odkaz: https://doi.org/10.1016/j.microrel.2017.05.015
  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    This paper deals with the operation of neutron irradiated 1700V SiC V-JFET in proposed DC-DC converters. The influence of irradiated V-JFET on the function of DC-DC converters are investigated. The measured results are compared with TCAD MixedMode simulation.

Radiation Damage in 4H-SiC and Its Effect on Power Device Characteristics

The Influence of Neutron Irradiation on Electrical Characteristics of 4H-SiC Power Devices

  • Autoři: prof. Ing. Pavel Hazdra, CSc., Popelka, S., Ing. Vít Záhlava, CSc.,
  • Publikace: Silicon Carbide and Related Materials 2014. Uetikon-Zurich: Trans Tech Publications, 2015. p. 785-788. Materials Science Forum. ISSN 0255-5476. ISBN 978-3-03835-478-9.
  • Rok: 2015

Characterization and simulation of neutron irradiated JBS silicon carbide diode structures

  • Autoři: Popelka, S., prof. Ing. Pavel Hazdra, CSc., Ing. Vít Záhlava, CSc.,
  • Publikace: IC-MAST - 3rd International Conference on Materials and Applications for Sensors and Transducers. Zürich: Transtech Publications, 2014. pp. 151-154. Key Engineering Materials. ISSN 1013-9826. ISBN 9783038350514.
  • Rok: 2014

Effect of Neutron Irradiation on High Voltage 4H-SiC Vertical JFET Characteristics: Characterization and Modeling

High-Power Silicon p-i-n Diode With the Radiation Enhanced Diffusion of Gold

  • DOI: 10.1109/LED.2014.2298754
  • Odkaz: https://doi.org/10.1109/LED.2014.2298754
  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    Fast recovery p-i-n diode with anode p-n junction modified by the radiation-enhanced diffusion (RED) of gold is presented. The RED of gold is shown to provide the local lifetime control of excess carriers, the compensation of n-base doping profile from n-type to p-type, and the enhancement of concentration of two gold-related deep levels. The deep level Au−/0 (EC − 0.549 eV) controls the low-level lifetime, whereas the gold–hydrogen pair (EC − 0.215 eV) the high-level lifetime. This feature eliminates the drawback of negative temperature coefficient of forward voltage drop of the RED with palladium and platinum, where only a single deep level, which controls the high-level lifetime, is enhanced. The RED of gold provides the maximal reverse bias safe operation area at the annealing temperature of 600 °C, whereas the RED of palladium at 650 °C.

ON-state characteristics of proton irradiated 4H–SiC Schottky diode: The calibration of model parameters for device simulation

  • DOI: 10.1016/j.sse.2014.02.004
  • Odkaz: https://doi.org/10.1016/j.sse.2014.02.004
  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    4H silicon carbide Schottky diodes were irradiated by 550 keV protons with the aim to place the ion range into the low-doped n-type epitaxial layer. The diodes were characterized using DLTS, C–V profiling and forward I–V curves. Calibration procedure of model parameters for device simulation as been carried out. It is based on modeling the doping compensation of the n-type epitaxial layer caused by the deep acceptor levels resulting from radiation damage. It is shown that the agreement of simulated and measured forward I–V curves of proton irradiated diodes can be achieved, if the profiles of deep levels are calibrated with respect to irradiation dose, the degradation of electron mobility due to charged deep levels is accounted of and the Schottky barrier height is properly adjusted. The proposed methodology introduces a starting point for exact calibration of ion irradiated SiC unipolar devices.

Operation of 4H-SiC High Voltage Normally-off V-JFET in Radiation Hard Conditions: Simulation and Experiment

  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    This paper deals with effect of neutron irradiation on static and dynamic characteristics of high voltage 4H-SIC JFET

Point Defects in 4H-SiC Epilayers Introduced by 4.5 MeV Electron Irradiation and Their Effect on Power JBS SiC Diode Characteristics

Point defects in 4H-SiC epilayers introduced by neutron irradiation

Radiation defects produced in 4H-SiC epilayers by proton and alpha particle irradiation

  • DOI: 10.4028/www.scientific.net/MSF.740-742.661
  • Odkaz: https://doi.org/10.4028/www.scientific.net/MSF.740-742.661
  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    Electronic properties of radiation damage produced in 4H-SiC epilayer by proton and alpha particle irradiation were investigated and compared. 4H-SiC epilayers, which formed the low doped n-base of Schottky barrier power diodes, were irradiated to identical depth with 550 keV protons and 1.9 MeV alphas. Radiation defects were then characterized by capacitance deep-level transient spectroscopy and C-V measurements.

Effect of Ion Irradiation on Electrical Characteristics of 1200V SiC Schottky Diodes

  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    The effect of ion irradiation on electrical characteristics of SiC Schottky barrier power diodes was investigated. Diodes were irradiated from the anode side with 550 keV protons or 1.9 MeV alphas to place radiation defect maximum into the low doped epitaxial layer which formed the N-base of the diode. Radiation defects were then characterized by capacitance deep-level transient spectroscopy and their influence on diode static and dynamic characteristics was evaluated. Results show that low fluences of both proton and alpha particle irradiation have a negligible effect on dynamic and blocking characteristics of SiC power diodes. However, in contrast with silicon devices, the ON-state resistance of SiC diodes increases significantly already at very low fluences. This negative effect is given by high introduction rates of radiation defects in SiC due to the suppressed annihilation of primary damage.

Radiation Enhanced Diffusion of Nickel in Silicon Diodes

  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    High-power P-I-N diodes (2.5 kV, 150 A) with sputtered NiV and NiCr layers at anode were implanted by 10 MeV helium ions and subsequently annealed in the range 550 - 800 oC. The devices were characterized using XPS, DLTS and OCVD. Leakage current, forward voltage drop and reverse recovery measurements were measured as well. The Radiation Enhanced Diffusion (RED) of nickel was registered after 20 min. annealing between 675 and 725 oC. The evidence was provided by depth profiling (DLTS). The effect of the RED of nickel on device electrical parameters was evaluated. Contrary to the palladium, the RED of nickel is not sufficient for the local control of carrier lifetime in power devices.

Low-Temperature Diffusion of Transition Metals at the Presence of Radiation Defects in Silicon

  • DOI: 10.4028/www.scientific.net/SSP.178-179.421
  • Odkaz: https://doi.org/10.4028/www.scientific.net/SSP.178-179.421
  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    Low-temperature diffusion of Cr, Mo, Ni, Pd, Pt, and V in silicon diodes is compared in the range 450 - 800 degC. The devices were characterized using AES, XPS, DLTS, OCVD carrier lifetime and diode electrical parameters. The metal atoms are divided into two groups. The Pt and Pd form deep levels in increased extent at the presence of radiation defects above 600 degC, which reduces the excess carrier lifetime. It is shown as a special case that the co-diffusion of Ni and V from a NiV surface layer results fully in the concentration enhancement of the V atoms. The enhancement of the acceptor level V-/0 (EC - 0.203 eV) and donor level V0/+ (EC - 0.442 eV) resembles the behavior of substitutional Pts. The second group is represented by the Mo and Cr. They easily form oxides, which can make their diffusion into a bulk more difficult or impossible. Only a slight enhancement of the Cr-related deep levels by the radiation defects has been found above 700 degC.

Molybdenum and low-temperature annealing of a silicon power P-i-N diode

  • DOI: 10.1016/j.microrel.2010.09.021
  • Odkaz: https://doi.org/10.1016/j.microrel.2010.09.021
  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    High-power P+P-N-N+ diodes (VRRM = 2.5 kV, IFAV = 150 A) with sputtered Mo layer at anode were annealed in the range 550-800 C with and without the presence of radiation defects from helium implantation (10 MeV, 1 1012 cm2). The devices were characterized using DLTS, spreading resistance, OCVD lifetime, leakage current, forward voltage drop and reverse recovery measurements. The diffusion of Mo from the 50 nm thick surface layer was not registered even after 4 h between 550 and 800 C in a rough vacuum.

Doping Compensation for Increased Robustness of Fast Recovery Silicon Diodes

  • DOI: 10.1016/j.microrel.2009.09.014
  • Odkaz: https://doi.org/10.1016/j.microrel.2009.09.014
  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    High-power diodes with the radiation enhanced diffusion (RED) of Pd are shown to have much higher ruggedness during the reverse recovery compared to that of the Pt. Anode doping profiles measured by spreading resistance technique after a 10 MeV He implantation with subsequent annealing between 500 and 800 degC reveal different compensation effects between the Pd and Pt. The in-diffusing Pd converts the n-type background doping concentration of ND = 3 .1013 cm-3 in the position of radiation defects to that of a p-type with about one order higher concentration. The created low-doped p-layer significantly increases ruggedness of diodes during reverse recovery.

Evaluation of Low-Temperature Molybdenum Diffusion for Lifetime Control

  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    High-power P-I-N diodes (2.5 kV, 150 A) with sputtered Mo layer at anode were annealed in the range 550 - 800 oC with and without the previous 10 MeV helium implantation. The devices were characterized using DLTS, spreading resistance, OCVD lifetime, leakage current, forward voltage drop and reverse recovery measurements.

Fast recovery Radiation Enhanced Diffusion (RED) Diode: Palladium versus Platinum

  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    2.5 kV fast recovery diodes based on the Radiation Enhanced Diffusion of palladium and platinum are compared in electrical parameters in the application of fast swtching.

Neon implantation and the radiation enhanced diffusion of platinum for the local lifetime control in high-power silicon diodes

  • DOI: 10.1016/j.nimb.2009.06.111
  • Odkaz: https://doi.org/10.1016/j.nimb.2009.06.111
  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    We investigate the influence of the higher production rate of the divacancy for the purpose of radiation enhanced diffusion (RED). We also compare the standard implantation of light (He) and heavy ions (Ne) to quantify the concrete impact on diode electrical parameters.

The Radiation Enhanced Diffusion (RED) Diode Realization of a Large Area p+p-n-n+ Structure with High SOA

  • Autoři: prof. Ing. Jan Vobecký, DrSc., Ing. Vít Záhlava, CSc., Hemman, H. K., Arnold, A. M., Rahimo, R. M.
  • Publikace: Proceedings of 21st International Symposium on Power Semiconductor Devices and ICs. Piscataway: IEEE, 2009. p. 144-147. ISSN 1943-653X. ISBN 978-1-4244-3525-8.
  • Rok: 2009
  • DOI: 10.1109/ISPSD.2009.5158022
  • Odkaz: https://doi.org/10.1109/ISPSD.2009.5158022
  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    We introduce a fully functional high voltage and high current p+p-n-n+ diode based on Radiation Enhanced Diffusion (RED) technology. The diode was processed on a 100 mm wafer and can safely turn off 4 and 7 kA @ 140oC @ 1500 A/us for the diameters of 51 and 91 mm, resp. The RED diode has low leakage, excellent SOA capability under free-wheeling conditions, very good softness, and very high SOA with di/dt towards 10kA/us. Clamp-less operation is presented up to 1300 A with peak power above 15 MW at 125 oC for the 91 mm diodes.

P-i-N Diode with Burried Low Doped P-layer: Impact of Radiation Enhanced Diffusion from Sputtered Palladium on Device Parameters

  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    P-i-N Diode with burried low doped P-layer and the impact of the Radiation Enhanced Diffusion from Sputtered Palladium on device parameters is explained in more details.

Radiation Enhanced Diffusion of Implanted Palladium in a High-Power P-i-N Diode

A Palm-Sized Real-Time (RT) PCR

  • Autoři: Novák, L., Neužil, P., Pipper, J., Zhang, Ch., Ing. Vít Záhlava, CSc.,
  • Publikace: Proceedings of microTAS 2006 Conference. Tokyo: Japan Academic Association Inc., 2006. p. 332-334. ISBN 4-9903269-0-3.
  • Rok: 2006

Novel Methods of Local Lifetime Control in Semiconductors

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Helium Irradiated High-Power P-i-N Diode with Low ON-State Voltage Drop

Impact of the Electron, Proton and Helium Irradiation on the Forward I-V Characteristics of High-Power P-i-N Diode

  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    Experimental and simulation work showing the impact of irradiation on device characteristocs in a wide temperature range.

Axial Lifetime Control by Irradiation with Protons, Alphas, Low- and High-Energy Electrons: Impact on Silicon Power Diode Parameters

Forward I-V Characteristics of the Electron, Proton and Helium Irradiated High-Power P-i-N Diodes

New Methods of Local Lifetime Control

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PSpice v produktech Orcad a Cadence

Elektronika - součástky a obvody, principy a příklady

InAs/GaAs Lasers for Optical Communication: Preparation and Properties

Study of Power Diodes for Higher Reliability and Energy Savings

New Recombination Centers for Modern Power Electronics

Open Circuit Voltage Decay Lifetime of Ion Irradiated Devices

OrCAD pro Windows

  • Pracoviště: Katedra mikroelektroniky
  • Anotace:
    Kniha popisuje základní aspekty návrhu desek plošných spojů (DPS), tedy problematiku počítačového návrhu DPS, technologii výroby vícevrstvých DPS, osazování a pájení SMD, elektrické vlastnosti plošných spojů. Rozsáhlá část knihy je věnována elektromagnetické kompatibilitě (EMC) a s ní souvisejícími návrhovými pravidly. I když se při návrhu desek plošných spojů velmi efektivně využívá počítačů, neznamená to, že navrhovat DPS na počítači je pouhé klikání myší. Počítačové návrhové systémy jsou jen účinné nástroje, usnadňující práci návrhářů. Návrh DPS vyžaduje především (ač to tak na první pohled nevypadá) komplexní znalosti v oblastech:technologie výroby desek plošných spojů (DPS),osazování a pájení,obvodové funkce součástek,teorie elektromagnetického pole a především jejich skloubení a využití v praxi. Cílem knihy je upozornit čtenáře na nejdůležitější problémy, které bude muset zdolat při návrhu elektronických schémat a desek plošného spoje. Návrhářem se člověk nestane pouze čtením publikací, ale aktivní mravenčí dlouhodobou prací, sbíráním zkušeností a zpětných vazeb z celého výrobního procesu navrhovaného zařízení, tedy od technologů z výroby DPS a osazování, odborníků ze zkušebních laboratoří EMC, servisních techniků a dalších. V praxi to znamená nejen "se učit, se učit, se učit", ale i "komunikovat, komunikovat, komunikovat", přijímat kritiku a poučit se nejen z vlastních chyb. méně textu

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Za stránku zodpovídá: Ing. Mgr. Radovan Suk