Structure Oriented Compact Model for Advanced Trench IGBTs without Fitting Parameters for Extreme Condition: part I

2011 22nd European Symposium on Reliability of Electron Devices, Failure Physics and Analysis, ESREF 2011, Oct 3-7, 2011, Universit Bordeaux 1, Domaine Haut Carr, Agora Talence, FranceA device structure based compact model for advanced trench gate IGBTs is proposed. The model is formulated only with device structure parameters so that no fitting parameters are required. The model is applicable to extreme conditions such as under very low or high temperatures. The validity of the model formulation is confirmed with two-dimensional TCAD simulation for voltage range of 1.2kV and 3.3kV IGBTs, and for temperature range of 300K and 450K. In this paper conduction mode formulation is proposed which has the potential to be used for system level failure analysis

Flavor Symmetry Breaking and Vacuum Alignment on Orbifolds

Flavor symmetry has been widely studied for figuring out the masses and mixing angles of standard-model fermions. In this paper we present a framework for handling flavor symmetry breaking where the symmetry breaking is triggered by boundary conditions of scalar fields in extra-dimensional space. The alignment of scalar expectation values is achieved without referring to any details of scalar potential and its minimization procedure. As applications to non-abelian discrete flavor symmetries, illustrative lepton mass models are constructed where the S3 and A4 flavor symmetries are broken down to the directions leading to the tri-bimaximal form of lepton mixing and realistic mass patterns.Comment: 21 page

IGBT chip current imaging system by scanning local magnetic field

An IGBT / power diode current distribution imaging system was demonstrated. This system can capture current redistribution or oscillation inside or among chips on a DBC-level sub-module. It can perform failure analysis of power semiconductors by detecting problems such as nonuniform current distribution between bonding wires. The system scans the chip’s shape using a laser sensor and then records the local magnetic field near the bonding wire using a 4-axis robot coil sensor. The coil sensor has two pair of Cu patterned spiral coils symmetrically arranged on both sides of a 60-μm-thick polyimide film. The system enables the analysis of destructive current concentrations of the entire chip, among chips or a part of the chip under high current or high voltage switching conditions, without making any changes or disassembling the chip connections.24th European Symposium on Reliability of Electron Devices, Failure Physics and Analysis. Schedule, September 30-October 4, 2013, Venue, Arcachon, Franc

Real time degradation monitoring system for high power IGBT module under power cycling test

A “real time” monitoring system which enables to observe internal degradation process to failure of power semiconductors under power cycling test is proposed. The system was realized by combining a scanning acoustic tomography (SAT/SAM), power stress controlling, device cooling, water jet system and chip temperature monitoring. Two contradictory problems, namely, electrically wiring for power cycling and waterproof of device for SAT imaging were compatible with each other by experimental setup with an original water tank. Self-heating of power devices was supressed by controlling temperature of water which is couplant of ultrasonic wave for the SAT. A demonstration of this system was performed by using an IGBT module which maximum rating of collector current was 400 A (DC).24th European Symposium on Reliability of Electron Devices, Failure Physics and Analysis. Schedule, September 30-October 4, 2013, Venue, Arcachon, Franc

Failure Analysis of Power Devices Based on Real-Time Monitoring

The aim is to provide failure analysis of power devices based on real-time monitoring. The real-time monitoring provides a time-domain data related to a failure mechanism. The data includes important information about primary failure, which is often lost by conventional post-defect failure analysis. Our system monitors interfaces of component material inside the device by scanning acoustic tomography (SAT) under a power cycling test in addition to electrical and thermal condition of the device. A precursor of the failure in an early stage was indicated by the interface image much earlier than a thermal and an electrical technique. Feature identification and extraction from a series of image data by image processing efficiently pointed out the damaged site before the failure was occurred.ESREF 2015, 26th European Symposium on Reliability of Electron Devices, Failure Physics and Analysis, Oct 5-9, 2015, Centre de Congrès Pierre Baudis, Toulouse, Franc

Structure Oriented Compact Model for Advanced Trench IGBTs without Fitting Parameters for Extreme Condition: Part II

Compact model for expressing turn-off waveform for advanced trench gate IGBTs is proposed even under high current density condition. The model is analytically formulated only with device structure parameters so that no fitting parameters are required. The validity of the model is confirmed with TCAD simulation for 1.2 kV to 6.5 kV class IGBTs. The proposed turn-off model is sufficiently accurate to calculate trade-off curve between turn-off loss and saturation collector voltage under extremely high current conduction, so that the model can be used for system design with the advanced trench gate IGBTs.ESREF 2014, 25th EUROPEAN SYMPOSIUM ON RELIABILITY OF ELECTRON DEVICES,FAILURE PHYSICS AND ANALYSIS, Sep 29–Oct 3, 2014, Technische Universität Berli

New Power Module Integrating Output Current Measurement Function

This paper proposes a new power module concept that integrates output current measurement function to make inverters compact. The current measurement function is realized by tiny printed-circuit-board (PCB) Rogowski coils. The PCB Rogowski coil picks up a switching current flowing through an IGBT chip, and then a combination of a digital circuit based on a field-programmable-gate-array (FPGA) and an integrator circuit reproduces the output current of the inverter from the switching current. A major concern of the new power module is the effect of reverse recovery current of free-wheeling diodes because the reverse recovery current is superimposed on the switching current. This paper proposes a mitigating method of the reverse recovery current.2017 29th International Symposium on Power Semiconductor Devices and IC\u27s (ISPSD), May 28 2017-June 1 2017, Sapporo, Japa

Micro PCB Rogowski coil for current monitoring and protection of high voltage power modules

We have developed a printed circuit board Rogowski coil for monitoring of current and protection of high-voltage power modules and packages. It is small, thin, and inexpensive current sensor and is almost the ideal Rogowski coil because of its fishbone pattern. For noise reduction under high-voltage/-current conditions in a module, shield layers and coaxial connector are employed. In addition, a new, fast simulation tool was developed to optimize the main coil pattern for realization of arbitrary printed circuit board geometry in specific, limited spaces

VLSI architectures for computing multiplications and inverses in GF(2-m)

Finite field arithmetic logic is central in the implementation of Reed-Solomon coders and in some cryptographic algorithms. There is a need for good multiplication and inversion algorithms that are easily realized on VLSI chips. Massey and Omura recently developed a new multiplication algorithm for Galois fields based on a normal basis representation. A pipeline structure is developed to realize the Massey-Omura multiplier in the finite field GF(2m). With the simple squaring property of the normal-basis representation used together with this multiplier, a pipeline architecture is also developed for computing inverse elements in GF(2m). The designs developed for the Massey-Omura multiplier and the computation of inverse elements are regular, simple, expandable and, therefore, naturally suitable for VLSI implementation

Temperature rise measurement for power-loss comparison of an aluminum electrolytic capacitor between sinusoidal and square-wave current injections

DC-link capacitors are a major factor of degrading reliability of power electric converters because they usually have a shorter lifetime and higher failure rate than those of semiconductor devices or magnetic devices. Characteristics of the capacitors are usually evaluated by a single sinusoidal current waveform. However, actual current flowing out of the converter into the capacitor is a modulated square current waveform. This paper provides experimental comparison of the power loss dissipated in an aluminum electrolytic capacitor between sinusoidal and square-wave current injections. Power loss is estimated by temperature rise of the capacitor. Experimental results confirm that power losses of the square-wave current injection were always lower than those of the sinusoidal current injection by 10–20%. Moreover, the power losses of the square-wave current injection can be estimated by a synthesis of fundamental and harmonic currents based on the Fourier series expansion, which brings a high accuracy less than 1% when more than fifth harmonic current is introduced. This comparison will be useful for estimating power loss and life time of electrolytic capacitors