A new MOS-gated power thyristor structure with turn-off achieved bycontrolling the base resistance

A new MOS-gated power thyristor structure, called the base-resistance-controlled thyristor (BRT), is described. In this structure, the turn-off of a thyristor with an N-drift region is achieved by reducing the resistance of the P-base region under MOS-gate control. In contrast with previous devices, a P-channel MOSFET integrated in the N-drift region is used for this purpose. It has been shown, by two-dimensional numerical simulations and experimental measurements on devices fabricated using a seven-mask process, that devices with 600-V forward blocking capabilities can be achieved with a forward drop close to that for a thyristor. The ability to turn off the thyristor current flow has been verified over a broad range of current densities     

A new lateral MOS-controlled thyristor

A lateral MOS-controlled thyristor (LMCT) structure that uses an MOS gate to turn it both on and off is presented. The device structure offers improved maximum turn-off current capability and forward voltage drop. The former is achieved by using a DMOS transistor and a parasitic vertical p-n-p transistor, while the latter is achieved by eliminating a parasitic lateral p-n-p transistor in the conventional structure. The device utilizes the resurf technique to achieve high area efficiency, breakdown voltage, and reliability. Devices that have more than 250-V forward blocking capability were fabricated in dielectrically isolated silicon tubs using the standard bipolar-CMOS-DMOS process     

The MOS-gated emitter switched thyristor

A monolithic device structure for obtaining MOS-gate-controlled turn-off of a thyristor is described. The device, called the emitter switched thyristor (EST), is designed so that the thyristor current flows through an enhancement-mode MOSFET, integrated into the base region of the thyristor, during the on state. Although this results in a small (0.25 V) increase in the forward voltage drop, it is demonstrated that excellent turn-off characteristics can be obtained, with typical turn-off of less than 1 μs     

The IBMCT: a novel MOS-gated thyristor structure

This paper addresses the analysis of the Insulated Base MOS-Controlled Thyristor (IBMCT), a novel MOS-thyristor structure compatible with IGBT process technology. The IBMCT turn-off process is based on the existence of a Floating Ohmic Contact (FOC) which allows fast hole removal from the p-body region. The device operation mode and its electrical characteristics are analyzed with the aid of 2-D numerical simulations. Experimental measurements confirm the ability to control both turn-on and turn-off processes by biasing the two independent gate electrodes. A comparison of the electrical characteristics with those obtained from IGBT and BRT is also provided     

A new lateral anode switched thyristor (LAST) with currentsaturation and low turn-off time

A novel MOS-gate controlled thyristor, entitled lateral anode switched thyristor (LAST), which exhibits a high current saturation and a low turn-off time, is proposed and successfully fabricated. Experimental results show that the new LAST achieves a current saturation capability larger than 1200 A/cm² even at high anode voltages. The forward voltage drop of LAST is 1.2 V at 100 A/cm ² where 10 V was biased to the dual gates. The turn-off time of LAST without any lifetime-control process is 1.5 μs while that of LAST without p⁺ diverter is about 2.9 μs. Our experimental data indicates that the p⁺ diverter successfully diverts holes in the drift region during the turn-off and a turn-off time is considerably decreased in the proposed LAST. The LAST, where any trouble-some parasitic thyristor mechanism is eliminated, completely suppresses a latch-up and increases the maximum controllable current considerably     

A CMOS compatible lateral emitter switched thyristor with enhancedturn-on capability

A new Lateral Emitter Switched Thyristor structure (LEST) is proposed and experimentally verified. The structure differs from the conventional LEST in that it embeds a floating ohmic contact between the n^- drift region and the n⁺ floating emitter. Both simulation and experimental results show that the device has an enhanced turn-on capability compared with the conventional LEST without deteriorating its other characteristics. The device is fabricated using a 3 μm CMOS process to have a 320 V breakdown voltage and a 0.7 V threshold voltage. Thyristor turn-on is observed at an anode voltage below 2 V. The maximum MOS controllable current density is in excess of 200 A/cm² with 5 V gate voltage     

The COMFET—A new high conductance MOS-gated device

A new MOS gate-controlled power switch with a very low on-resistance is described. The fabrication process is similar to that of an n-channel power MOSFET but employs an n^--epitaxial layer grown on a p⁺substrate. In operation, the epitaxial region is conductivity modulated (by excess holes and electrons) thereby eliminating a major component of the on-resistance. For example, on-resistance values have been reduced by a factor of about 10 compared with those of conventional n-channel power MOSFET's of comparable size and voltage capability.     

Dielectrically isolated lateral emitter switched thyristor

The operation of a 500 V dielectrically isolated lateral emitter switched thyristor (DI-LEST) is described for the first time. Experimental devices exhibit an on-state voltage drop of 2.35 V at a current density of 100 A/cm/sup 2/, and a maximum controllable current density of about 200 A/cm/sup 2/. The on-state voltage drop decreases with increasing drift layer thickness consistent with the uniform lateral current flow observed in two-dimensional numerical simulations.<>     

自保护MOS栅晶闸管

本文报告一种叫做自保护MOS栅晶闸管的新器件.这种器件无寄生闩锁效应,并在较高阳极电压下展现出电流下降而不是饱和或上升的特性.因此,这种新器件具有令人满意的正偏安全工作区.器件的保护点由用户外接输入电阻自行调节,极大增加了使用的灵活性.此外,器件保护点电流和电压的温度系数均为负,这种特性使器件在高温工作时可更好地起自保护作用.     

New CMOS compatible junction-isolated lateral base resistancecontrolled thyristor

A new 550 V lateral base resistance controlled thyristor structure is proposed and its operation is rigorously characterised by two-dimensional numerical simulation in the off-state, on-state, and turn-off transient mode. Simulations indicate a 40% lower forward voltage drop over a comparable LIGBT, and a superior switching property over other competing lateral thyristor structures     

The MGBT: a new MOS-gated power bipolar transistor

A new device called the MGBT is described in which the upper regions of the device structure are conductivity-modulated by a positive feedback mechanism to give a lower on-state voltage drop compared to a power DMOSFET while having fast switching and fully gate-controlled characteristics. In the MGBT, a P⁺ injector coupled to the drain potential by a vertical driver DMOSFET in an emitter-switched configuration is used to inject holes which is then diverted to the entire surface region of the device by a novel cell design. 750 V MGBT devices fabricated along with DMOSFET devices on the same wafer showed 33% improvement in current density at room temperature and 46% improvement at 75°C at a forward drop of 3.5 V. The turn-off time of the MGBT was 80 ns equal to that of the DMOSFET     

Physical fundamentals and technical aspects of the lateral thyristor

Different types of the lateral thyristor as well as their way of functioning and their properties with various modes of operation are described and compared. Particular attention has been paid to the problem of turning off the thyristor operated with direct voltage. In the comparative reflections, a type of the lateral thyristor is included which is not available commercially, but which as a turn-off thyristor offers some advantages in comparison to other types. This epitaxial lateral thyristor was produced at our laboratory and thoroughly examined—including the component structures it contains (epitaxial lateral transistor, P⁺NN⁺ diode).     

Dual-channel EST/BRT: a new high-voltage MOS-gated thyristorstructure

A new MOS-gated thyristor structure, in which a BRT section is incorporated into the dual-channel EST (DC-EST) to enhance maximum controllable current densities, is presented. This structure has been demonstrated experimentally to have a maximum controllable current density about 2.5 times greater than that of the DC-EST, with only a small increase in the on-state voltage drop     

A new static induction thyristor (SITh) analytical model

In this paper, an analytical static induction thyristor (SITh) model is proposed based on device internal physical operating mechanisms. The nonquasi-static model predicts both device static and dynamic characteristics. The model accounts for effects of the device structure, lifetime, and temperature. Implemented in PSPICE as a subcircuit, model simulation results are compared with numerical simulation and experiment results for various electrical and thermal conditions. The model exhibits accurate results, good convergence, and fast simulation speed     

Experimental observation of the lateral plasma propagation in a thyristor

Electron-hole plasma propagation in the lateral direction of a thyristor is slowed down by emitter shunts. The lifetimes of the device also influence the plasma-spreading velocity. These phenomena are observed by taking time-resolved pictures of recombination radiation emission from the device.     

一种具有高正向阻断电压及优良开关特性的新型静电感应晶闸管

设计并构造了一种具有条状阳极P-缓冲层结构（SAP-B）的新型静电感应晶闸管。该结构以具有p- 缓冲层和嵌入p+发射区（条状阳极区）的弱掺杂n-发射区（泄漏阳极区）为特点。与传统扩散源区埋栅结构相比,SAP-B结构可进一步简化工艺,并将扩散源区埋栅结构静电感应晶闸管的正向阻断电压从1000V提高至1600V,阻断增益从40提高至70,同时将关断时间从0.8μs降低至0.4μs。     

Design of MOS-gated bipolar transistors with integral antiparalleldiode

This paper discusses the design of a new power switching device with integral antiparallel diode called MOS gated bipolar transistor (MGBT). The upper region of the MGBT device structure is conductivity-modulated by a positive feedback mechanism to give a lower on-state voltage drop as compared to a power MOSFET while having fast switching and fully MOS-gate controlled characteristics. A comprehensive model for the MGBT is developed and simple analytical equations are used to predict the on-state characteristics of the MGBT. The analytical modeling results are in good agreement with experimental results on fabricated 750 V MGBT devices. The experimentally measured characteristics of the integral antiparallel diode in the MGBT are reported for the first time in this paper     

A new static induction thyristor with high forward blocking voltage and excellent switching performances

A new static induction thyristor (SITH) with a strip anode region and p~- buffer layer structure (SAP-B) has been successfully designed and fabricated. This structure is composed of a p~- buffer layer and lightly doped n~-regions embedded in the p~+-emitter. Compared with the conventional structure of a buried-gate with a diffused source region (DSR buried-gate), besides the simple fabrication process, the forward blocking voltage of this SITH has been increased to 1600 V from the previous value of 1000 V, the blocking gain increased from 40 to 70, and the turn-off time decreased from 0.8 to 0.4μs.     

A double-gate-type static-induction thyristor

A double-gate-type static-induction thyristor (DG-SIThy) with a high blocking voltage and a high current rating has been fabricated. In this paper, a basic operational mechanism, a fabrication procedure, and the electrical characteristics of the DG-SIThy are described. In the DG-SIThy, both electron injection and hole injection are controlled by signals applied to two gale regions so that the DG-SIThy is capable of higher frequency operations than a single-gate SIThy. In the DG-SIThy, described here, both a cathode and a gate (first gate) regions have been fabricated on one side of a semiconductor wafer and both an anode and gate.(second gate) regions on another side. For realizing the DG-SIThy with a high blocking voltage and a high current rating, we have tried attentively to form a p-n junction on one side of the wafer without influencing the p-n junction on the other side, and have developed a new counter-doping technique for epitaxial growth and an improved package structure for a compression-mounted device. The DG-SIThy fabricated with these techniques has shown a for-Ward blocking voltage of 1000 V, an average current rating of 100 A, and a forward voltage drop of 1.44 V at the rated anode current. A turn-on time of 0.95 its and a turn-off time of 0.48 µs have been observed at the rated anode current and at anode voltages of 650 and 550 V, respectively. As already speculated, the DG-SIThy shows a higher switching speed and a lower forward drop than the single-gate SIThy.     

A base-current drive technique for saturating B.J.T's

A method of generating pulses of base current, for both the switch-on and switch-off phases of a common-emitter saturating b.j.t. switch, that avoids the use of the familiar "speed-up" capacitor is described. The method is used to produce, with long-established devices, voltage pulses of adjustable amplitude, and edge speeds faster than 1 V/ns.