M. Sweet

A fast switching segmented anode NPN controlled LIGBT

An ultrafast low energy loss lateral insulated gate bipolar transistor (LIGBT) with a novel segmented anode structure is demonstrated. The anode comprises segments of p/sup +/ and n/sup +//p (n/sup +/ region formed within a p-type region) along the width of the device. By simply varying the ratio of these segments the tradeoff between conduction and switching losses can be varied. Unlike an anode shorted structure this does not exhibit an undesirable snapback in its on-state characteristics. This structure is simple to realize in a CDMOS process without the need for any additional process steps.

MOS control device concepts for AC-AC matrix converter applications: the HCD concept for high-efficiency anode-gated devices

Reverse blocking MOS controlled devices will enable high efficiency ac-ac matrix converter systems to replace dc-linked type circuits. The trend in bidirectional switches is to replace the combination of a unidirectional blocking device and a diode with a monolithic reverse blocking device only. The diode on-state loss is eliminated, part count is reduced, and the system is less bulky. This paper discusses the various reverse blocking concepts suitable for MOS controlled devices for high voltage matrix converter applications. They include the junction isolation, the trench isolation, and the anode-gated (AG) concepts. AG is the only concept not technologically limited beyond 1200 V. However, increasing drift region thickness with voltage rating necessitates innovations to achieve fast switching and low losses without compromising V/sub ce(sat)/. Herein we propose the high channel density concept to further improve the efficiency of AG devices. Simulation results indicate the concept drastically reduces turnoff losses and improve switching speed.

Experimental Demonstration of 3.3kV Planar CIGBT In NPT Technology

Due to the desirable properties of MOS-gate control, low conduction losses at high voltages, MOS-controiled thyristor structures are preferred for applications at 3.3 kV and beyond. In this paper, we report the results of the first experimental demonstration of the 3.3 kV rated CIGBT (Clustered Insulated Gate Bipolar Transistor) with planar gates in NPT technology. CIGBT is a three terminal MOS- controlled thyristor. Our results show that, with a positive Vce(sat) temperature coefficient and for identical turn-off loss, its Vce(sat) can be more than 0.7 V lower than that of an IGBT. Moreover, for the same gate voltage, it is shown that CIGBT shows lower saturation current density compared to the IGBT. Additionally, due to controlled thyristor mode of operation, a more favourable trade-off performance can be obtained using lower anode implant doses without significantly compromising Vce(sat).

Experimental Demonstration of a 1.2kV Trench Clustered Insulated Gate Bipolar Transistor in Non Punch Through Technology

For the first time, we present experimental results of a trench clustered IGBT structures fabricated in 1.2kV non-punch-through technology. Experimental results demonstrate significantly low forward voltage drop in comparison to trench IGBTs in the same technology. Furthermore, results show that the use of dummy cells in the TCIGBT device can improve the trade-off between the on-state and turn-off losses

Anode Engineering for the Insulated Gate Bipolar Transistor—A Comparative Review

Significant effort has been placed in anode engineering for the insulated gate bipolar transistor (IGBT) as a method to enhance the on-state/switching loss tradeoff. For the first time, we have taken a comprehensive selection of these designs and individually implemented them all into a 1200 V vertical structure. It is shown that all passive anode engineering structures lie on or above a forward voltage drop/inductive turn-off loss tradeoff curve which can also be generated through changing the emitter (anode) Gummel number of a conventional IGBT. Tradeoff enhancement can be achieved through the use of active anode structures. Such structures incorporate an additional gate at the anode and are considered in the study. The influence of lifetime on the tradeoff is considered and it is shown that optimum device performance can be achieved through both control of the lifetime and the emitter Gummel number/anode engineering. The relative shift in the tradeoff curve is also considered for optimum device design. Furthermore, the effect of the tradeoff curve on the total power loss with varying switching frequency and duty cycle is also discussed. high temperature operation, it is shown that the shift must be carefully considered for optimum device design. Furthermore, the effect of the tradeoff curve on the total power loss with varying switching frequency and duty cycle is also discussed.

Performance analysis of the segment npn anode LIGBT

The performance of a high-voltage lateral insulated gate bipolar transistor (LIGBTs) with segmented n+p/n anode fabricated in junction isolation technology is experimentally investigated at both room and elevated temperatures. Detailed two dimensional numerical modeling of a vertical representation of the structure shows that significant electron current passes through the n/sup +/p/n segment of the anode region during the on-state and when devices are subjected to clamped inductive switching. It is shown that the magnitude of electron current can be controlled by modifying the p-base charge which enables enhancement of the turn-off loss/forward voltage drop tradeoff in comparison to conventional LIGBTs.

Design and analysis of multichannel LIGBTs in junction isolation technology

Performance of multichannel lateral insulated gate bipolar transistors (MC-LIGBTs) fabricated in a cost-effective, fully implanted, CDMOS-compatible process in junction isolation technology is reported. Due to the presence of additional MOS cathode cells, the MC concept enables a reduction in the forward voltage drop. Furthermore, the MC concept is combined with the segmented N/sup +/P/P/sup +/ anode (SA-NPN) concept in an LIGBT structure. The SA-NPN anode concept reduces turnoff losses due to a reduction in injection of holes and from the collection of electrons by the narrow base-collector shorted NPN bipolar transistor formed at the anode. It is shown that combining the MC and the SA-NPN Anode concepts creates a device that exhibits both low on-state and turnoff losses and thus best placed for use in power IC applications.

Numerical Evaluation of the Short-Circuit Performance of 3.3-kV CIGBT in Field-Stop Technology

In this paper, the short-circuit performance of a conventional 3.3-kV clustered insulated gate bipolar transistor (CIGBT) in field-stop (FS) technology is evaluated through extensive 2-D numerical simulations. For comparison, an equivalent 3.3-kV FS IGBT is considered. The conventional CIGBT shows superior performance of lower on-state voltage drop and saturation current densities in comparison to an equivalent IGBT. Further improvements to the CIGBT performance can be obtained without sacrificing on-state voltage drop by using a PMOS trench gate. The charge balance and electric field distribution with the varying n-buffer thickness at short-circuit condition are analyzed in detail.

A novel gate geometry for the IGBT: the trench planar insulated gate bipolar transistor (TPIGBT)

This letter demonstrates a simple way to improve the performance of a planar, fine lithography insulated gate bipolar transistor (IGBT), by incorporating a trench gate between the cathode cells. The results of this new trench-planar IGBT (TPIGBT) clearly demonstrate a significant reduction in the voltage drop without degrading the breakdown voltage. The switching analysis indicates that the TPIGBT represents a good trade-off between planar and trench structures. By separating the trench gate requirements away from the cathode cells, the technology development cycle and costs can be reduced. Furthermore, the reduced cell-width and the shallow trench presents TPIGBT as a cost-effective structure for high-voltage applications.

RC-TCIGBT: A Reverse Conducting Trench Clustered

A new, three terminal, reverse conducting trench clustered IGBT (RC-TCIGBT) is proposed and evaluated using numerical simulations in 1200 V, non-punch through (NPT) technology. This device is a monolithic integration of an anti- parallel thyristor (APT) in the TCIGBT (O. Spulber, et. al., December 2000), (K. Vershinin, et. al., June 2006). This approach does not increase device area and ensures snap-back free operation in the first (Ist) and third (IIIrd) quadrants. Moreover, it is shown that the RC-TCIGBT which belongs to the class of MOS bipolar devices with controlled thyristor action, can provide excellent Vce (sat)/Eoff trade-off and soft reverse recovery.