金属氧化物半导体控制晶闸管的di/dt优化

金属氧化物半导体控制晶闸管(MCT)相比于绝缘栅双极型晶体管(IGBT)具有高电流密度、低导通压降和快速开启等优势,在高压脉冲功率领域具有广阔的应用前景.作为脉冲功率开关,MCT开启过程对输出脉冲信号质量有很大影响.采用理论分析并结合仿真优化重点研究了MCT开启瞬态特性.通过对MCT开启过程进行详细地理论分析推导,给出了MCT开启过程中阳极电流和上升时间的表达式.结合Sentaurus TCAD仿真优化,将MCT开启过程中电流上升速率(di/dt)由40 kA/s提升至80 kA/s,极大地改善了器件开启瞬态特性.最后,总结提出了提高器件开启瞬间di/dt的设计途径.     

Analysis of insulated gate transistor turn-off characteristics

A model based upon a MOSFET driving a wide-base p-n-p transistor is presented for analysis of the turn-off behavior of n-channel insulated gate transistors. This model is found to provide a very good quantitative explanation of the shape of the collector current waveform during turn-off. Verification was accomplished using insulated gate transistors (IGT's) fabricated with two voltage ratings and a variety of radiation doses. This analysis allows the separation of the channel (electron) and minority carrier (hole) current flow in the IGT for the first time.     

Experimental and numerical study of the emitter turn-off thyristor(ETO)

The emitter turn-off thyristor (ETO) is a new family of high power semiconductor devices that is suitable for megawatt power electronics application. ETOs with voltage and current ratings of 4-6 kV and 1-4 kA, have been developed and demonstrated. And those power levels are the highest in silicon power devices and are comparable to those of the gate turn-off thyristor (GTO). Compared to the conventional GTO, the ETO has much shorter storage time, voltage controlled turn-off capability, and much larger reverse biased safe operation area (RBSOA). Furthermore, ETOs have a forward-biased safe operation area (FBSOA) that enables it to control the turn-on di/dt similar to an insulated gate bipolar transistor (IGBT). These combined advantages make the ETO based power system simpler in terms of dv/dt snubber, di/dt snubber, overcurrent protection, resulting in significant savings in the system cost. This paper presents experimental and numerical results that demonstrate the advantages of the ETO     

Power Converter EMI Analysis Including IGBT Nonlinear Switching Transient Model

It is well known that very high dv/dt and di/dt during the switching instant is the major high-frequency electromagnetic interference (EMI) source. This paper proposes an improved and simplified EMI-modeling method considering the insulated gate bipolar transistor switching-behavior model. The device turn-on and turn-off dynamics are investigated by dividing the nonlinear transition by several stages. The real device switching voltage and current are approximated by piecewise linear lines and expressed using multiple dv/dt and di/dt superposition. The derived EMI spectra suggest that the high-frequency noise is modeled with an acceptable accuracy. The proposed methodology is verified by experimental results using a dc-dc buck converter     

Lateral insulated gate p-i-n transistor (LIGPT)-a new MOS gatelateral power device

A new insulated gate power device suitable for thin silicon-on-insulator (SOI) application is described and verified through two-dimensional numerical simulation. The lateral insulated gate p-i-n transistor (LIGPT) has a much superior current carrying capability than that of the lateral insulated gate bipolar transistor (LIGBT) because it conducts like a p-i-n diode. Because a new turn-off mechanism is employed, the LIGPT also demonstrates a very large gate turn-off capability. These two major advantages; coupled with other advantages such as latch-up free, make the LIGPT a very promising device for use in power integrated circuits on SOI     

具有积累层沟道的槽栅IGBT结构

提出了一种具有积累层沟道的槽栅IGBT结构。仿真结果表明：在阻断电压为1200V,集电极电流密度为100 A/cm2,温度分别为300K和400K下的情况下,积累层沟道槽栅IGBT的正向压降分别为1.5V 和2V而常规槽栅IGBT分别为1.7V和2.4V。新结构比常规槽栅IGBT具有更低的开态压降和更大的正向安全工作区。文中同时分析了积累层沟道槽栅IGBT的阻断特性和关断特性。     

Switching speed enhancement in insulated gate transistors by electron irradiation

High-speed switching in insulated gate transistors (IGT's) has been achieved by using electron irradiation. This technique allows excellent control over the switching speed with the ability to reduce the gate turn-off time from over 20 µs to under 200 ns. This increase in speed is accompanied by an increase in the forward voltage drop during current conduction. This necessitates performing a trade-off between switching and conduction losses. Despite the increase in the forward drop, the IGT's exhibit superior characteristics in comparison with power MOSFET's and bipolar transistors up to switching frequencies of 100 kHz.     

Insulated gate bipolar transistor with trench gate structure of accumulation channel

An accumulation channel trench gate insulated gate bipolar transistor (ACT-IGBT) is proposed. The simu-lation results show that for a blocking capability of 1200 V, the on-state voltage drops of ACT-IGBT are 1.5 and 2 V at a temperature of 300 and 400 K, respectively, at a collector current density of 100 A/cm~2. In contrast, the on-state voltage drops of a conventional trench gate IGBT (CT-IGBT) are 1.7 and 2.4 V at a temperature of 300 and 400 K,respectively. Compared to the CT-IGBT, the ACT-IGBT has a lower on-state voltage drop and a larger forward bias safe operating area. Meanwhile, the forward blocking characteristics and turn-off performance of the ACT-IGBT are also analyzed.     

An investigation of the drive circuit requirements for the powerinsulated gate bipolar transistor (IGBT)

The drive circuit requirements of the insulated gate bipolar transistor (IGBT) are explained with the aid of an analytical model. It is shown that nonquasi-static effects limit the influence of the drive circuit on the time rate-of-change of anode voltage. Model results are compared with measured turn-on and turn-off waveforms for different drive, load, and feedback circuits, and for different IGBT base lifetimes     

Novel passive lossless turn-on snubber for voltage source inverters

A novel passive lossless turn-on snubber with a soft-clamped turn-off snubber circuit for voltage source inverters is proposed. The energy trapped in the snubber is recovered into the DC supply and load without any active devices, associated control circuitry, or resistors. The overshoot voltage on the switches is clamped, and the peak switch current is low, making this snubber suitable for use in high-power insulated gate bipolar transistor (IGBT) inverters     

A new gate driver integrated circuit for IGBT devices with advanced protections

The aim of this paper is to discuss new solutions in the design of insulated gate bipolar transistor (IGBT) gate drivers with advanced protections such as two-level turn-on to reduce peak current when turning on the device, two-level turn-off to limit over-voltage when the device is turned off, and an active Miller clamp function that acts against cross conduction phenomena. Afterwards, we describe a new circuit which includes a two-level turn-off driver and an active Miller clamp function. Tests and results for these advanced functions are discussed, with particular emphasis on the influence of an intermediate level in a two-level turn-off driver on overshoot across the IGBT.     

The di/dt capability of thyristors

This paper describes an experimental investigation of the di/dt failure mechanism of thyristors. The location of the initial turn-on region and the spread of the "on" region were observed on a specially designed thyristor having many monitoring electrodes. The turn-on process was studied for triggering by gate, by breakover, and by dv/dt. In many cases it was found that turn-on occurred at almost the same region, whether it was triggered by breakover or by dv/dt. This area coincided with the final holding position in the turn-off process. The di/dt capability of the thyristor was measured. It was found that the capabilities were almost the same for the three triggering methods. The destruction temperature in the di/dt test was estimated from the area of the burn-out spots and the energy dissipation.     

Shorter turn-off times in insulated gate transistors by proton implantation

Proton implantation has been used to shorten the turnoff time of insulated gate transistors. A narrow region of low carrier lifetime was created at 100-µm depth by implanting 3.1-MeV protons. As with other techniques of lifetime control, an increase in forward voltage drop with decreasing turn-off time was observed. The use of localized lifetime control provides the opportunity of improving the trade-off relationship between turn-off time and forward voltage drop at the device's operating current. A definite improvement in trade-off curves was observed when the new technique of proton implantation was compared to the method of electron irradiation.     

4.5-kV injection-enhanced gate transistors (IEGTs) with high turn-off ruggedness

Although high blocking voltage insulated gate bipolar transistors (IGBTs) have wider safe operating areas (SOAs) than do gate turn-off thyristors, a failure problem remains at turn-off transient. The purpose of this paper is to clarify the mechanism of failure at turn-off transient and to develop a high-voltage injection-enhanced gate transistors (IEGTs) with wide SOA at turn-off transient [wide reverse-biased SOA (RBSOA)]. We discuss this destruction mechanism in detail on the basis of comparison of experimental results with calculated results obtained by an analytical model considering dynamic avalanche generation. These results lead to the conclusion that the design of the n-emitter and the control of avalanche generation onset are key parameters for realizing high ruggedness of high-voltage IEGT. Based on the proper design of the n-emitter and the gate driving condition, a high-voltage and high-current 4.5-kV IEGT with wide RBSOA, keeping low saturation voltage and low turn-off switching loss, has been successfully developed.     

New Lossless Turn-On and Turn-Off (Snubber) Networks for Inverters, Including Circuits for Blocking Voltage Limitation

Transistorized pulsewidth modulated (PWM) inverters require careful dimensioning of turn-on and turn-off circuits in order to minimize switching loss in the power transistors. New lossless circuits are described. In particular the turn-off circuits show a highly reduced part count compared to circuits known from the literature. The turn-on circuits apply energy recovery. Furthermore, due to a special circuit the voltage across the power transistor is strictly limited. This is important especially due to the usually low voltage blocking capability of high-current power transistors.     

Multiple Slope Switching Waveform Approximation to Improve Conducted EMI Spectral Analysis of Power Converters

An improved and simplified electromagnetic interference (EMI) modeling method based on multiple slope approximation of device-switching transitions for EMI analysis of power converters is presented. The traditional noise source modeling method, which uses single slope for rise and fall transition, is studied, and the criteria for reasonable modeling in the frequency range is analyzed. The turn-on and turn-off dynamics are investigated by dividing the nonlinear transitions into several stages based on an insulated gate bipolar transistor (IGBT) behavior circuit model. Real device-switching voltage and current waveforms are approximated by piece-wise linear lines and modeled by multiple dv/dt and di/dt slopes. The predicted EMI spectra suggest that high-frequency EMI noise is modeled with an acceptable accuracy. The proposed method was verified experimentally for a dc-dc buck converter     

The insulated gate transistor: A new three-terminal MOS-controlled bipolar power device

A new three-terminal power device, called the insulated gate transistor (IGT), with voltage-controlled output characteristics is described. In this device, the best features of the existing families of bipolar devices and power MOSFET's are combined to achieve optimal device characteristics for low-frequency power-control applications. Devices with 600-V blocking capability fabricated using a vertical DMOS process exhibit 20 times the conduction current density of an equivalent power MOSFET and five times that of an equivalent bipolar transistor operating at a current gain of 10. Typical gate turn-off times have been measured to range from 10 to 50 µs.     

Inductive switching of 4H-SiC gate turn-off thyristors

The high-temperature operation of a silicon carbide gate turn-off thyristor is evaluated for use in inductively loaded switching circuits. Compared to purely resistive load elements, inductive loads subject the switching device to higher internal power dissipation. The ability of silicon carbide components to operate at elevated temperatures and high power dissipations are important factors for their use in future power conversion/control systems. In this work, a maximum current density of 540 A/cm² at 600 V was switched at a frequency of 2 kHz and at several case temperatures up to 150°C. The turn-off and turn-on characteristics of the thyristor are discussed     

Assessment of off-state negative gate voltage requirements forIGBTs

This paper addresses the need for off-state negative gate bias with insulated gate bipolar transistor (IGBT) devices that experience a dv/dt when in the off state. Factors considered include off-state gate bias voltage, gate impedance, reapplied dv/dt, and temperature. Theoretical calculation and experimental results for a high-voltage high-current IGBT supports the assessment of these factors     

SiGe-collector trench gate insulated gate bipolar transistor fabricated using multiple target sputtering

A new type of trench gate IGBT (insulated gate bipolar transistor) which uses a SiGe layer for the collector is experimentally investigated. SiGe collectors with different Ge content are deposited by multiple cathode sputtering making low temperature processing possible. The change in turn-off characteristics with Ge content is also investigated. Results indicate that the use of a SiGe collector reduces the tail current at turn-off due to the reduced injection of holes to the n⁻ drift region.