Munaf Rahimo

The Bi-mode Insulated Gate Transistor (BIGT) a potential technology for higher power applications

In this paper, an advanced Reverse Conducting (RC) IGBT concept is presented. The new technology is referred to as the Bi-mode Insulated Gate Transistor (BIGT) implying that the device can operate at the same current densities in transistor (IGBT) mode and freewheeling diode mode by utilizing the same available silicon volume in both operational modes. The BIGT design concept differs from that of the standard RC-IGBT while targeting to fully replace the state-of-the-art two-chip IGBT/Diode approach with a single chip. The BIGT is also capable of improving the over-all performance especially under hard switching conditions.

A High Current 3300V Module Employing Reverse Conducting IGBTs Setting a New Benchmark in Output Power Capability

In this paper we demonstrate a fully functional high voltage and high current IGBT module rated at 3300 V consisting solely of reverse conducting (RC) IGBT chips. The RC- IGBTs were designed in accordance with the latest Enhanced Planar and Soft Punch Through technology while incorporating an integrated freewheeling diode in the same silicon volume. Future high power IGBT modules with RC-IGBT technology will be capable of providing exceptional electrical performance for the given voltage class in terms of the maximum allowable output current capability.

Limitation of the short-circuit ruggedness of high-voltage IGBTs

In this paper, the destruction mechanism, which limits the short-circuit capability of high voltage IGBTs utilizing N-buffer structures will be described. The failure mechanism was studied using a combination of device simulations and experimental investigations of 3.3kV, 4.5kV and 6.5kV IGBTs. It was found that the limiting short-circuit failure in these IGBTs is caused by a current filamentation mechanism, which is associated to a distortion of the electric field triggered by a positive feedback effect between the carrier drift velocities and the electric field and the resulting potential distribution in the IGBT N-base.

Novel Enhanced-Planar IGBT Technology Rated up to 6.5kV for Lower Losses and Higher SOA Capability

In this paper, we introduce an IGBT planar technology, which sets a new performance benchmark in terms of losses and SOA capability. The improved trade-off relationship between on-state losses Vce(sat) and turn-off losses Eoff (i.e. technology curve) was solely realized by means of planar cell enhancement. Simultaneously, high levels of turn-off ruggedness (RBSOA) were obtained with the new cell design. The enhanced-planar IGBT technology is implemented on the soft-punch-through (SPT) buffer concept for ensuring controllable and soft switching behaviour. The paper covers design details of the enhanced-planar technology and a full set of results for the 6500V EP-IGBT chip

1200V IGBTs operating at 200°C? An investigation on the potentials and the design constraints

The targeted 175degC junction temperature limit for the next generation of 1200 V IGBT requires safe and reliable operation of the devices at a temperature of 200degC. Due to the exponential scaling of several IGBT parameters, such high temperatures will subject the IGBT to new levels of stress, guiding chip designers and application people onto completely new grounds whose firmness is largely unknown. In this paper, we take some first steps by investigating the operation of 1200 V IGBTs at temperatures up to 200degC, looking at their characteristics, trying to understand potentials and possible threats, and drawing initial conclusions how such devices must be dimensioned in order to operate safely.

A Landmark in Electrical Performance of IGBT Modules Utilizing Next Generation Chip Technologies

The aim of this work is to demonstrate that future high power IGBT modules will be capable of providing electrical performance not matched to date in terms of low losses, soft turn-off characteristics, square RBSOA, and full over-current and over-voltage self-protection mechanisms under fault conditions. First ever prototype modules were fabricated incorporating heavily paralleled 3300V chips employing the next generation enhanced-planar IGBT (EP-IGBT) technology and the field charge extraction diode (FCE) concept. In this paper, we show that the two technologies will provide the module with outstanding characteristics, therefore promising higher levels of performance in tomorrows applications. In addition, we present a set of results where two 3300V IGBT modules were tested in parallel under extreme RBSOA conditions with a forced temperature difference of up to 100 degC. The modules were capable of turning off 6000A at a DC-link voltage of 2600V in spite of the temperature induced current mismatch and associated redistribution mechanisms

The Radiation Enhanced Diffusion (RED) Diode realization of a large area p+p-n-n+ structure with high SOA

In this paper, we introduce a fully functional high voltage (V<inf>rrm</inf>= 4.5 kV) and high current (I<inf>FM</inf>= 7 kA) p⁺p⁻n⁻n⁺ diode based on Radiation Enhanced Diffusion (RED) technology. The RED-Diode employs a low-doped p-layer buried at ≈100 µm to increase the dynamic avalanche ruggedness for high SOA capability. The diode was processed on a 100 mm wafer and can safely turn off 4 and 7 kA @ 140°C @ 1500 A/µs for the diameters of 51 and 91 mm, resp. The RED of Pd was also extended from He to H irradiation. Compared to the reference diode without the buried p-layer, the RED diode has equal leakage, equal SOA capability under free-wheeling conditions, similar softness, 30% and 50% higher SOA for 51 and 91 mm diodes resp. with di/dt towards 10kA/µs. Clamp-less operation is presented up to 1300 A with peak power above 15 MW at 125 °C for the 91 mm diodes. For clamping diode application, this ruggedness can be further improved.

Novel Approach Toward Plasma Enhancement in Trench-Insulated Gate Bipolar Transistors

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.

Inherently soft free-wheeling diode for high temperature operation

Traditionally, the major driver in IGBT and diode development is to minimize the static and dynamic losses. A significant reduction of the n-base thickness would yield this, however it can also jeopardize the switching characteristic leading to high overshoot voltages during diode reverse recovery. In this paper, we present an improved Field-Charge Extraction (FCE) concept that is achieving a soft reverse recovery behavior inherently. The new design allows for a 10% reduction of the thickness of the diodes n-base, while still maintaining the blocking capability and the softness of the conventional diode. Therefore, the technology curve and the ruggedness are improved significantly.

Experimental demonstration of the p-ring FS+ Trench IGBT concept: A new design for minimizing the conduction losses

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.