基于IGBT模块饱和压降温度特性的结温探测研究

实验室条件下,IGBT模块的结温探测是瞬态热阻抗测试的关键。首先分别在热稳态和热瞬态下证明了饱和压降温度特性只与芯片有关,然后建立了IGBT模块结温探测模型,利用饱和压降值和集电极电流值来计算结温值,并将用模型计算出的结温与光纤实测的结温相比较,吻合性良好,证明了模型计算法能够准确探测结温。该方法可以用于恒流加热过程中瞬态热阻抗的测量,比起热敏参数法中冷却过程测量瞬态热阻抗相比,更具有实际意义。     

Pulse measurements of transient thermal response and temperature of avalanching p?n junction

A method is presented for measuring the junction temperature and the transient thermal response of oscillator-mounted avalanche diodes; the method requires an exact knowledge of the temperature dependence of the diode breakdown voltage. The junction temperature can be measured with unchanged accuracy within the measured temperature range of the breakdown voltage. The transient response as close as a few microseconds after the initiation of the junction-temperature step can be measured.     

High temperature current–voltage characteristics of InP‐based tunnel junctions

In this paper, we present temperature‐dependent current–voltage measurements of tunnel junctions lattice matched to InP at temperatures ranging from room temperature to 220 °C. Temperature‐dependent tunneling properties were extracted by fitting the current–voltage characteristics using a simple analytical formula. Three different designs of tunnel junction were characterized, including a bulk InAlGaAs tunnel junction, an InAlGaAs tunnel junction with InAlAs cladding layers and an InGaAs/InAlGaAs quantum‐well tunnel junction. Each device exhibited different temperature dependence in peak tunnel current and excess current, with the quantum‐well tunnel junction exhibiting the greatest temperature sensitivity. We use a non‐local tunneling model, in conjunction with a numerical drift‐diffusion solver, to explain the performance improvement available by using double heterostructure cladding layers around the junction region, and use the same model to explain the observed temperature dependence of the devices. Copyright © 2014 John Wiley & Sons, Ltd.     

Instantaneous junction temperature evaluation of high-power diodes(thyristors) during current transients

In this paper, an approach to the instantaneous junction temperature evaluation of high-power diodes (thyristors) is presented. The model allows obtaining the instantaneous junction temperature waveform starting from the expressions of the device transient thermal impedance and forward voltage drop. The linearity properties of resistors and capacitors (RCs) networks are used to obtain the thermal system transfer function from the transient thermal impedance curve. Thus, an expression that relates the forward voltage drop to the forward current and the junction temperature is used to “feedback” the influence of the temperature variation on the device forward characteristic. The model is also validated by comparing the results obtained from simulation against the one obtained from surge tests performed on one sample device     

Effect of collector voltage and collector current on junction temperature

Experiments have been carried out on the 2N929 transistor to investigate the effect of collector voltage and collector current on junction temperature. The results indicate that at constant power dissipation increasing the collector voltage will increase the junction temperature and give the apparent effect of a higher thermal resistance.     

Effect of junction temperature on the large-signal properties of a 94 GHz silicon based double-drift region impact avalanche transit time device

The authors have developed a large-signal simulation technique extending an in-house small-signal simulation code for analyzing a 94 GHz double-drift region impact avalanche transit time device based on silicon with a non-sinusoidal voltage excitation and studied the effect of junction temperature between 300 and 550 K on the large-signal characteristics of the device for both continuous wave(CW) and pulsed modes of operation.Results show that the large-signal RF power output of the device in both CW and pulsed modes increases with the increase of voltage modulation factor up to 60%,but decreases sharply with further increase of voltage modulation factor for a particular junction temperature;while the same parameter increases with the increase of junction temperature for a particular voltage modulation factor.Heat sinks made of copper and type-IIA diamond are designed to carry out the steady-state and transient thermal analysis of the device operating in CW and pulsed modes respectively. Authors have adopted Olson’s method to carry out the transient analysis of the device,which clearly establishes the superiority of type-IIA diamond over copper as the heat sink material of the device from the standpoint of the undesirable effect of frequency chirping due to thermal transients in the pulsed mode.     

一体化封装LED结温测量与发光特性研究

基于一体化封装基板,制备了大功率白光LED。以低热阻的一体化封装基板为基础,设计了结温测量系统。利用光谱仪测得不同结温下LED的光电参数,并对其机理进行了分析。在工作电流为0.34A,所研究温度范围为10.8～114.9℃。实验结果表明,一体化封装的LED结温与正向电压、光通量、光效和色温有着良好的线性关系;结温的变化对主波长及色坐标影响甚微;结温的上升导致蓝光段强度下降且光谱发生红移,黄光段强度上升且光谱发生宽化,峰值波长由450nm转为550nm。     

A study on IGBT junction temperature (Tj) online estimation using gate-emitter voltage (Vge) at turn-off

A novel method is presented for online estimation of the junction temperature (Tj) of semiconductor chips in IGBT modules, based on evaluating the gate-emitter voltage (Vge) during the IGBT switch off process. It is shown that the Miller plateau width (in the Vge waveform) depend linearly on the junction temperature of the IGBT chips. Hence, a method can be proposed for estimating the junction temperature even during converter operation – without the need of additional thermal sensors or complex Rth network models. A measurement circuit was implemented at gate level to measure the involved time duration and its functionality was demonstrated for different types of IGBT modules. A model has been proposed to extract Tj from Vge measurements. Finally, an IGBT module with semiconductor chips at two different temperatures has been measured using Vge method and this method was found to provide the average junction temperature of all the semiconductor chips.     

Observation of resonant tunneling at room temperature inGaInP/GaAs/GaInP double-heterojunction bipolar transistor

Negative differential resistance (NDR) has been observed at room temperature in GaInP/GaAs double-heterojunction bipolar transistors (DHBTs). Both the common-emitter and common-base current-voltage characteristics and their magnetic field dependence have been studied to confirm that the observed NDR is due to resonant tunneling. The collector-base voltages at which the collector current resonances occur are calculated and are consistent with the measured values. The devices exhibit an offset voltage of 57 mV and saturation voltage of ⩽ 2-V, both of which are the lowest reported values for GaInP/GaAs DHBTs. The collector-base breakdown voltage in these DHBTs is 31 V, and its variation with junction temperature is measured and described     

The effect of electro-thermal parameters on IGBT junction temperature with the aging of module

This paper presents the effect of the change of electro-thermal parameters on IGBT junction temperature with module aging. Five IGBT modules are subjected to advance power thermal cycling, and IGBT I–V characterization, switching loss, and transient thermal impedance curve are measured every 1000 power thermal cycles. Then, electro-thermal models of IGBT module under power thermal cycles were built by change electro-thermal parameters, and the influence of various parameters of the electro-thermal model on the junction temperature was researched respectively. Experimental results demonstrate that IGBT collector-emitter voltage, switching loss and thermal resistance increase more quickly with the aging process of module. Simulation results indicate that the variations of electro-thermal parameters have crucial influences on the IGBT junction temperature. After 6000 power thermal cycles, the IGBT steady state junction temperature mean and variation are increased 1.97 K and 0.1656 K over its initial value, respectively. The relative temperature rise is 38.10% and relative temperature variation is 15.08% after 6000 power thermal cycles. The rise in switching loss increases both the steady state junction temperature mean and variation. The change of thermal impedance has great influence on the steady state junction temperature mean, but has little effect on steady state junction temperature variation.     

Investigations on junction temperature estimation based on junction voltage measurements

Reliability and ageing tests on power semiconductor devices require estimation of junction temperatures in order to control thermal stresses and monitor failure criteria. For this purpose, thermo-electrical parameters, such as voltage forward drop dependence with temperature are usually carried out in low injection level. Nevertheless, it is still difficult to evaluate the limits of such exploitation. An analytical model has been developed and validated by experimental measurements in order to evaluate self-heating effects and to understand high temperature effects. This model should also allow to highlight the role of some physical parameters in the voltage–temperature dependence and to clarify such thermal calibration.     

Internal processes in power semiconductors at virtual junction temperature measurement

High measurement accuracy is the basis for a precise determination of the junction temperature T_j. Temperature measurement can be performed by means of temperature sensitive parameters (TSP) using the V_CE(T)-method, however, internal semiconductor processes like the removal of stored charge in bipolar devices have to be respected. The aim of this work is to determine the earliest time point of accurate measurement t_MD after switching off, as well as dependencies on device voltage classes and applied battery voltage. Measurement results are confirmed by performing the simulation with Sentaurus TCAD. Dependencies of delay t_MD on temperature, applied measurement current and battery voltage are demonstrated for IGBT and silicon diode.     

液氮温区集成式数字温度传感器设计

温度传感器是制冷型红外焦平面探测器的重要组成部分,它用于测量探测器工作温度,其输出用于制冷机控制,从而控制探测器温度。探测器的工作温度将直接影响探测器的性能,如信噪比、探测率和盲元率等。针对传统PN结温度传感器需要模拟信号处理电路及易受电磁干扰的弊端,设计了一种基于CMOS工艺的集成式数字温度传感器,可以集成到红外焦平面探测器读出电路中,直接通过SPI接口输出数字测温值。设计的集成式数字温度传感器采用0.35 m CMOS工艺流片,芯片面积为380 m500 m（不包含PAD）,在电源电压2.5 V和采样频率6.1次/s条件下,功耗为300 W,分辨率0.061 6 K。在77 K温度下输出的RMS噪声为0.148 K。测试结果表明,集成式数字温度传感器可以应用于制冷型红外焦平面探测器温度测量。     

Elevated temperature nitrogen implants in 6H-SiC

Elevated temperature (700°C) N ion implantations were performed into 6H-SiC in the energy range of 50 keV-4 MeV. By analyzing the as-implanted depth distributions, the range statistics of the N⁺ in 6H-SiC have been established over this energy range. Annealing at 1500 and 1600°C for 15 min resulted in Rutherford backscattering spectrometry scattering yields at the virgin crystal level, indicating a good recovery of the crystalline quality of the material without any redistribution of the dopant. A maximum electron concentration of 2 × 10¹⁹ cm⁻³, at room temperature, has been measured even for high-dose implants. The p-n junction diodes made by N ion implantation into a p-type substrate have a forward turn-on voltage of 2.2 V, an ideality factor of 1.90, and a reverse breakdown voltage of 125 V with nA range leakage current for -10 V bias at room temperature. By probing many devices on the same substrate we found uniform forward and reverse characteristics across the crystal.     

High sensitive and wide detecting range MOS tunneling temperature sensors for on-chip temperature detection

This paper examined the feasibility of applying a highly sensitive metal-oxide-semiconductor (MOS) tunneling temperature sensor, which was compatible with current CMOS technology. As the sensor was biased positively at a constant voltage, the gate current increased more than 500 times when the sensor was heated from 20/spl deg/C to 110/spl deg/C. However, when the sensor was biased at a constant-current situation, its gate voltage magnitude changed significantly with substrate temperature, with a sensitivity exceeding -2 V//spl deg/C. The improvement of temperature sensitivity in this paper is one thousand times over the sensitivity of a conventional p-n junction, i.e., namely, about -2 mV//spl deg/C. Regarding a temperature sensor array, this paper proposes a method using gate current gain, rather than absolute gate current, to eliminate the gate current discrepancy among sensors. For constant current operation, a sensitivity exceeding 10 V//spl deg/C can be obtained if the current level is suitable. Finally, this paper demonstrates a real temperature distribution for on-chip detection. With such a high temperature-sensitive sensor, accurate temperature detection can be incorporated into common CMOS circuits.     

Impact of the gate driver voltage on temperature sensitive electrical parameters for condition monitoring of SiC power MOSFETs

Condition monitoring using temperature sensitive electrical parameters (TSEPs) is widely recognized as an enabler for health management of power modules. The on-state resistance/forward voltage of MOSFETs, IGBTs and diodes has already been identified as TSEPs by several researchers. However, for SiC MOSFETs, the temperature sensitivity of on-state voltage/resistance varies depending on the device and is generally not as high as in silicon devices. Recently the turn-on current switching rate has been identified as a TSEP in SiC MOSFETs, but its temperature sensitivity was shown to be significantly affected by the gate resistance. Hence, an important consideration regarding the use of TSEPs for health monitoring is how the gate driver can be used for improving the temperature sensitivity of determined electrical parameters and implementing more effective condition monitoring strategies. This paper characterizes the impact of the gate driver voltage on the temperature sensitivity of the on-state resistance and current switching rate of SiC power MOSFETs. It is shown that the temperature sensitivity of the switching rate in SiC MOSFETs increases if the devices are driven at lower gate voltages. It is also shown, that depending on the SiC MOSFET technology, reducing the gate drive voltage can increase the temperature sensitivity of the on-state resistance. Hence, using an intelligent gate driver with the capability of customizing occasional switching pulses for junction temperature sensing using TSEPs, it would be possible to implement condition monitoring more effectively for SiC power devices.     

一种测试功率MOSFET热阻的新方法

阐述了一种测试功率MOSFET热阻的新方法。该方法选取漏源电流作为温度敏感参数,在相同漏源电压和栅源电压幅度下,当栅源电压条件由直流形式变为脉冲形式时,漏源电流是有差异的,这一差异是由结温的不同造成的。而脉冲栅源电压下环境温度的调整可以用来模拟直流条件下的结温,由此可以测得器件在直流条件下的热阻。该方法具有精度高、实现容易和操作方便等优点,可作为功率MOS器件结温和热阻的有效测试方法。     

Forward and reverse current–voltage–temperature characteristics of a typical BPW34 photodiode

The dark forward and reverse current–voltage characteristics of a typical BPW34 silicon photodiode have been investigated in the temperature range 80–300 K. We propose that tunnelling enhanced recombination at or close to the p/i interface plays a significant role in the dark forward current. We show that Bardeen’s model for a modified Schottky-like interfacial junction can be satisfactorily applied to describe the reverse current–voltage characteristics at intermediate bias voltages.     

Degradation of the parameters of transistor temperature sensors under the effect of ionizing radiation

The influence of the effective concentration of an impurity specifying the conduction type of the base region and the base thickness on the radiation resistance of transistor temperature sensors is investigated. The dependences of the forward voltage drop at the emitter transistor junction and current amplification factor on the magnitude of electron, neutron, and γ-quanta flows are revealed. It is found that degradation of the forward voltage drop under the effect of ionizing radiation begins at doses higher by almost two orders of magnitude than the current amplification factor depending on the transistor’s design features. The reproducibility of the temperature-sensitive parameter, which increases the yield percentage of suitable devices, increases after annealing of the electron-irradiated structures.     

一种利用发光光谱估计LED正向电压的方法

提出了一种通过发光光谱估计发光二极管(LED)正向电压的方法。推导了LED正向电压与结温的关系,探讨了利用发光光谱估计结温的方法,从而建立了发光光谱和正向电压的联系。本文方法不需要直接测量结温和理想因子等参数,只由发光光谱就可得到较为准确的LED正向电压值。实验结果表明,正向电压的光谱估计值和实际测量值能够较好的吻合。