In this letter, we present the “anode-side” SuperJunction trench field stop+ IGBT concept with drift region SuperJunction pillars placed at the anode side of the structure rather than the cathode side. The extent of the pillars toward the cathode side is shown to pose a tradeoff between fabrication technology capabilities (and cost) versus the device performance, by extensive TCAD simulations. The proposed device structure simplifies the fabrication requirements by steering clear from the need to align the cathode side features with the SuperJunction pillars. It also provides an extra degree of freedom by decoupling the cathode design from the SuperJunction structure. Additionally, the presence of SuperJunction technology in the drift region of the “anode-side” SJ Trench FS+ IGBT results in 20% reduction of ON-state losses for the same switching energy losses or, up to 30% switching losses reduction for the same ON-state voltage drop, compared with a 1.2-kV breakdown rated conventional FS+ Trench IGBT device. The proposed structure also finds applications in reverse conducting IGBTs, where a reduced snapback can be achieved, and in MOS-controlled thyristor devices.

An approach to implement electrically robust MOSFETs in a functioning half-bridge will be investigated. For the first time, reverse conducting 3.3kV SiC MOSFETs have been fabricated with dilferent cell pitches from 14μm (p1.0) to 26μm (pl.8) that are able to withstand short circuit pulse of up to 10μs and a 9ms surge current event up to 15x the nominal current. LinPak half-bridge modules have been fabricated showing reduction of the switching loss by more than 90% compared to a silicon IGBT/diode half bridge.

In this paper, we present and discuss simulation and experimental results obtained from investigating the impact of local alterations of the electric field profile in the power device planar junction termination region. Such local modifications are due to possible various extrinsic causes (manufacturing, operational or environmental) and are shown to have a critical influence on the device voltage blocking capability and reliability. The results point towards junction termination sensitivity to locally modified fields especially under voltage switching conditions due to higher leakage current densities in the modified area compared to the rest of the JT region.

Very low voltage, 60-600 V insulated-gate bipolar transistors (IGBTs) were compared to power mosfet s with conventional and superjunction drift layers of identical voltage classes using mixed-mode numerical device simulation. This study was done in the light of forthcoming 400 V class IGBTs for use in electric vehicle/hybrid electric vehicle: the 600 V borderline, which previously separated the bulk of power mosfet from IGBT applications, has become fragile recently. We find that the 400 V class must not represent a lower limit for IGBTs based on silicon: in fact, LV IGBTs could offer lower losses down to the 60-100 V level. Most importantly, low-voltage IGBTs may outperform power mosfets not only with respect to on-state voltage drop but also regarding switching offering up to 30% lower turn-off losses. This paper presents physics-based arguments focusing on the device transconductance to augment these projections. LV IGBTs or hybrid devices (monolithic integration of mosfet plus IGBT) could become lower cost, high performance alternatives to SJ power mosfets thanks to short development cycles common in mature silicon technologies.

In this letter, a trench-insulated gate bipolar transistor (IGBT) design with local charge compensating layers featured at the cathode of the device is presented and analyzed. The superjunction or reduced surface effect proves to be very effective in overcoming the inherited ON-state versus breakdown tradeoff appearing in conventional devices, such as the soft punch through plus or field stop plus (FS+) IGBTs. This design enhances the ON-state performance of the FS+IGBT by increasing the plasma concentration at the cathode side without affecting either the switching performance or the breakdown rating.

A new IGBT type structure, namely the p-ring FS+ Trench IGBT, with improved performance has been demonstrated. The improvement has been achieved through the utilization of p doped buried layers (p-rings) which allows for the simultaneous increase in the n enhancement layer doping concentration above the conventional levels without compromising the device breakdown rating. This unique lateral charge compensation approach is demonstrated to be highly effective in lowering the on-state losses. The experimental results show a 20% reduction in the on-state losses for a 1.7kV device.

This paper focuses on the causes that lead to the final destruction in standard gate-commutated thyristor (GCT) devices. A new 3-D model approach has been used for simulating the GCT which provides a deep insight into the operation of the GCT in extreme conditions. This allows drawing some conclusions on the complex mechanisms that drive these devices to destruction, previously impossible to explain using 2-D models.

In this letter, we report E-off-versus-V-ce tradeoff curves for vertical superjunction insulated-gate bipolar transistors (SJ IGBTs), exhibiting unusual inverse slopes dE(off)/dV(ce) > 0 in a transition region between purely unipolar and strongly bipolar device behaviors. This effect is due to the action of p-pillar hole current when depleting the drift layer of SJ IGBTs during turnoff and the impact of current gain on the transconductance. Such SJ IGBTs surpass by a very significant margin their superjunction MOSFET counterparts in terms of power-handling capability and ON-state and turnoff losses, all at the same time.

In this paper we propose novel designs that enhance the plasma concentration across the Field Stop IGBT. The “p-ring” and the “point-injection” type devices exhibit increased cathode side conductivity modulation which results in impressive IGBT performance improvement. These designs are shown to be extremely effective in lowering the on-state losses without compromising the switching performance or the breakdown rating. For the same switching losses we can achieve more than 20% reduction of the on state energy losses compared to the conventional FS IGBT.

15 years ago the vertical SuperJunction (SJ) concept conceived for SJ power MOSFETs was the last, major breakthrough in the field of silicon power devices. Today, the SuperJunction MOSFET technologies have reached a mature stage characterized by gradual performance improvements. SuperJunction Insulated Gate Bipolar Transistors (SJ IGBTs) could interrupt this stagnation holding promise to revitalize voltage classes from 600 up to 1200 V. Such SJ IGBTs surpass by a very significant margin their SJ MOSFET counterparts both in terms of power handling capability, on-state and turn-off losses, all at the same time. On the higher end of the voltage class, SJ IGBTs would top the performance of 1.2 kV IGBTs by a similar margin.

Advanced silicon impact-ionization models are linked with simple accurate 1-D breakdown-voltage formulas for p-n step junctions. The models are useful for ab initio calculations and improve the accuracy of older models due to a new parameterization based on a numerical simulation. New parameters for effective impact-ionization coefficients are presented for Chynoweth and Fulop formulations. The parameter sets are based on impact-ionization models of Van Overstraeten and De Man and of the Universita di Bologna, including its recent updates. They allow quick computing of silicon p-n junction breakdown voltages from 10 V to 10 kV with maximum deviation from numerical data of ±5%. The new breakdown-voltage models account for the junction temperature and the depletion on both sides of the p-n junction.

The termination design of superjunction (SJ) structures has always been a conceptual and technological challenge. In this letter, we propose new, optimized, elegant, and cost-efficient solutions toward the realization of the first 1.2-kV rated SJ insulated-gate bipolar transistor. The design is based on the utilization of existing layers in the device fabrication line, hence resulting in no extra complexity or cost increase. The proposed design effectiveness is confirmed through extensive numerical simulations.

The aim of this paper is to demonstrate the application of the superjunction (SJ) design in an insulated gate bipolar transistor (IGBT). Bipolar conduction is present and enhanced at the cathode side of the device, while the p-pillars collect the plasma deep from the anode side, thus significantly enhancing its turn-off speed. The disconnected soft punchthrough+ (SPT+) SJ IGBT is similar to the SJ IGBT, which we have previously reported, but the drift region pillars do not extend up to the cathode contact. Instead, the upper part of this device is similar to the SPT+ IGBT, i.e., it features an n+ injector around the p-well and the n-drift region that is lightly doped. The improvement in the overall performance is impressive (25% lower ON-state losses and 30% lower switching losses) and can indeed justify the technology cost associated with the SJ technology. We also demonstrate how this technology can be used to form a snapback-free reverse conducting IGBT.

In this letter, we propose a new device, the Semi-Superjunction (SJ) (Semi-SJ) insulated-gate bipolar transistor (IGBT) (Semi-SJ IGBT). The device offers significant improvement in the on state and switching tradeoff compared with the state-of-the-art FieldStop Trench IGBT (FS IGBT). Furthermore, when compared with a full SJ IGBT, the device has a considerably simpler process of manufacturing as the existing fabrication process for the “CoolMOS” could be used. The Semi-SJ IGBT offers better robustness against cosmic rays compared with an FS IGBT; the failure-in-time per surface area (FIT/A) of the device levels are up to two orders of magnitude lower. Alternatively, by changing the structure parameters, one can improve dramatically the on state versus switching tradeoff while maintaining the same FIT/A levels.

In this paper, we present a detailed analysis and optimization of the superjunction (SJ) insulated gate bipolar transistor (IGBT). The SJ IGBT is a new device that breaks the IGBT limits, i.e., it delivers performance that is dramatically better. More specifically, we demonstrate here that the optimized SJ IGBT can deliver turn-off losses that are at least 50% lower than those of the state-of-art IGBT while maintaining a similarly low ON-state performance, both at room temperature and at higher temperatures. The presence of alternating p- and n-pillars in the drift region gives rise to unique characteristics that when optimized can deliver superior performance. This paper also presents a SPICE model of the SJ IGBT under optimized conditions. Its results are in good agreement with the DESSIS simulation results under direct current conditions. This model consists of an intrinsic MOSFET and a parallel combination of wide- and narrow-base p-n-p bipolar junction transistors.

In this paper we present a new design approach which dramatically improves the robustness of power semiconductor device against cosmic rays induced breakdown. This failure mode occurs during continuous operation at a DC rail voltage, which in practice is well below the breakdown rating (typically half of the breakdown). This failure is more prominent for higher breakdown rated devices (above 2kV) and represents one of the main causes of concern, especially if the power systems are operated at higher altitude. Using a mathematical model for the calculation of the cosmic ray breakdown failure rate proposed by Zeller [1], we show that by employing a SuperJunction structure in the drift region of a high voltage diode we can achieve a great improvement in the robustness of the device against cosmic ray radiation. Since the cosmic ray failure rate is strongly dependent on the electric field distribution, the two-dimensional nature of the SuperJunction electric field with lower peaks and more even distribution offers a huge advantage over the use of standard PiN devices. Finally, a physical two-dimensional electric field model for the SuperJunction structures is developed which is then imported into Zeller’s model to compute the cosmic ray failure rate for different DC voltage rails.

In this paper we present a new device, the 3.3kV semi-SuperJunction Reverse Conducting Insulated Gate Bipolar Transistor that can help to alleviate the voltage snapback of the Reverse Conducting IGBT while we achieve significant improvement in the on-state vs switching trade-off performance of the IGBT. The introduction of the SuperJunction structure in the drift region of the RC IGBT reduces the effective on-state resistance under unipolar current conduction. This ultimately affects the voltage snapback value as well as the reverse recovery of the diode while turn off.

In this paper we propose and describe a new device, the 3.3 kV semi-superjunction insulated gate bipolar transistor (Semi SJ IGBT). The device offers significant improvement in the on-state and switching trade-off compared to both state-of the-art field stop (FS) trench IGBT and the Full SJ IGBT; There is no need for very deep pillars, therefore the ease of manufacturing is improved as the device can be based on the dasiapresentpsila CoolMOS type technology for formation of n & p pillars for 600-1 kV. This makes the device a potential winner for the 3.3 kV or even greater voltage ranges (e.g. 6.5 kV). Furthermore the device offers considerably better robustness against cosmic rays when compared to a conventional FS IGBT. Here we demonstrate via analytical modeling that the FIT (Failure in Time) levels can be improved by one to two orders of magnitude.