Application Note, V1.3, May 2008 CoolMOS TM 900V New 900V class for superjunction devices A new horizon for SMPS and renewable energy applications Power Management & Supply Edition 2008-05-13 Published by Infineon Technologies AG 81726 Munich, Germany © 2008 Infineon Technologies AG All Rights Reserved. Legal Disclaimer The information given in this document shall in no event be regarded as a guarantee of conditions or characteristics. With respect to any examples or hints given herein, any typical values stated herein and/or any information regarding the application of the device, Infineon Technologies hereby disclaims any and all warranties and liabilities of any kind, including without limitation, warranties of non-infringement of intellectual property rights of any third party. Information For further information on technology, delivery terms and conditions and prices, please contact the nearest Infineon Technologies Office (www.infineon.com). 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CoolMOS™ 900V New 900V class for superjunction devices A new horizon for SMPS and renewable energy applictions CoolMOSTM 900V Revision History: 2008-05 Previous Version: V1.1 03.04.2008 Modified chapter 3.2 13.05.2008 Disclaimer+Fig. 9 actual. V1.3 We Listen to Your Comments Any information within this document that you feel is wrong, unclear or missing at all? Your feedback will help us to continuously improve the quality of this document. Please send your proposal (including a reference to this document) to: [email protected] Application Note 3 V1.3, 2008-05 CoolMOS™ 900V New 900V class for superjunction devices A new horizon for SMPS and renewable energy applictions Table of Contents Page 1 1.1 Introduction...............................................................................................................................................5 The Superjunction Principle ........................................................................................................................6 2 Device characteristics..............................................................................................................................8 3 3.1 3.2 3.3 3.4 Target applications CoolMOSTM 900V ...................................................................................................10 Wide range designs (90…270Vac) with their typical 400Vdc bulk voltage ................................................10 Replacement of IGBTs by CoolMOS™ 900V Series.................................................................................14 Lighting applications .................................................................................................................................15 Auxiliary power supplies in 3-phase systems............................................................................................15 4 Product Portfolio ....................................................................................................................................16 5 5.1 5.2 5.3 5.4 5.5 Circuit Design and Layout Recommendations.....................................................................................17 Control dv/dt and di/dt by Proper Selection of Gate Resistor ....................................................................17 Minimize Parasitic Gate-Drain Board Capacitance ...................................................................................17 Locate Gate Drivers and Gate Turn-Off Components as Close as Possible to the Gate...........................18 Use Symmetrical Layout for Paralleling MOSFETs, and Good Isolation of Gate Drive between FETs .....18 Summary ..................................................................................................................................................18 References ........................................................................................................................................................19 Application Note 4 V1.3, 2008-05 CoolMOS™ 900V New 900V class for superjunction devices A new horizon for SMPS and renewable energy applictions 1 Introduction Infineon introduces a new 900V voltage class of energy-saving CoolMOS switch-mode power supply and renewable energy applications. TM power MOSFETs for high efficiency TM CoolMOS 900V offers extremely low static and dynamic losses, which is the signature of super junction MOSFET technology where the so-called “silicon limit” is overcome. The square-law dependency between onresistance and blocking voltage in conventional MOSFETs is amended by new CoolMOSTM 900V, resulting in an industry-best on-state resistance per package type being four times or even lower if compared to conventional 900V MOSFETs: 0.12 Ohm in TO247, 0.34 Ohm in TO220, and 1.2 Ohm in DPAK packages. A figure-of-merit (FOM) on-resistance times gate charge (RDSon*QG) as low as 34 Ω*nC is reached, which translates into extremely low conduction, driving and switching losses. Samples are available now and the complete product spectrum will be filled up during 2008. Target applications for CoolMOSTM 900V are ATX power supplies, solar converters, quasiresonant flyback designs for LCD TV, active frontend 3-phase-systems and other designs, were high blocking voltage, low conduction and switching losses combined with low gate charge are necessary. Table 1 gives a quick overview of available CoolMOSTM series today. Table 1 CoolMOSTM Series at a Glance Market Entry Voltage Class [V] Special Characteristic CoolMOSTM S5 1998 600 Low RDS(on), Switching speed close to standard MOSFETs CoolMOSTM C3 2001 500/600/ 650/800 CoolMOSTM CFD 2004 CoolMOSTM CP CoolMOSTM C3 Application Note Vgs,th Gfs [V] [S] Internal Rg [Ω] 4.5 Low High Fast switching speed symmetrical rise/fall time at VGS=10 V 3 High Low 600 Fast body diode, Qrr 1/10th of C3 series 4 High Low 2005 500/600 Ultra-low RDS(on), ultra-low Qg, very fast switching speed 3 High Low 2008 900 low RDS(on), low Qg, fast switching speed 3 High Low 5 V1.3, 2008-05 CoolMOS™ 900V New 900V class for superjunction devices A new horizon for SMPS and renewable energy applictions 1.1 The Superjunction Principle CoolMOSTM is a revolutionary technology for high voltage power MOSFETs and designed according to the superjunction (SJ) principle [1], which in turn is based on the RESURF [2] ideas being successfully used for decades in lateral power MOSFETs. Conventional power MOSFETs suffer from the limitation of the so-called “silicon limit” [3], which means that doubling the voltage blocking capability typically leads to an increase in the on-state resistance by a factor of five. The “silicon limit” is shown in Figure 1 where the area specific on-state resistance of state-of-the-art standard MOSFETs as well are indicated. SJ technology may lower the on-state resistance of a power MOSFET virtually towards zero. The basic idea is to allow the current to flow from top to bottom of the MOSFET in very high doped vertically arranged regions. In other words, a lot more charge is available for current conduction compared to what is the case in a standard MOSFET structure. In the blocking state of the SJ MOSFET, the charge is counterbalanced by exactly the same amount of charge of the opposite type. The two charges are separated locally in the device by a very refined technology, and the resulting structure shows a laterally stacked fine-pitched pattern of alternating arranged p- and n-areas, see Figure 2. The finer the pitch can be made, the lower the on-state resistance of the device will be. Area specific resistance [Ohm*mm2] 40 30 20 State-of-the-art conventional MOS 10 "Silicon Limit" CoolMOSTM 0 500 Figure 1 600 700 800 Blocking voltage [V] 1000 Area-specific on-resistance versus breakdown voltage comparison of standard MOSFET TM and CoolMOS Technology S G G S n p+ pp n+sub D - - - n epi - - D Standard MOSFET Figure 2 900 Superjunction MOSFET Schematic Cross-Section of a Standard Power MOSFET versus a Superjunction MOSFET Application Note 6 V1.3, 2008-05 CoolMOS™ 900V New 900V class for superjunction devices A new horizon for SMPS and renewable energy applictions Another signature of SJ technology is the extremely fast switching speed. The turn off behavior of a SJ MOSFET is not characterized by the relatively slow voltage driven vertical expansion of the space charge layer but by a sudden nearly intrinsic depletion of the laterally stacked p-n structure. This unique behavior makes the device very fast. The neutralization of these depletion layers is done via the MOS controlled turn-on of the load current for the n-areas and via a voltage driven drift current for the p-areas. SJ devices reach therefore theoretical rise and fall times in the range of few nanoseconds. Figure 3 shows a comparison of RDS(on),max between today’s most advanced available MOSFETs. 1.4 1.3 Best in Class TO-220 CoolMOS Infineon 1.2 Best in Class TO-220 Superjunction Competitor Best in Class TO-220 Standard Technology Competitor RDS(on) [Ohm] 1 0.75 0.8 0.6 0.5 0.43 0.4 0.4 0.27 0.23 0.2 0.14 0.14 0.34 0.29 0.19 0.099 0.13 0 500V Figure 3 600V 650V 800V 900V Comparison of RDS(on),max for most advanced MOSFETs in TO220 package available in the market. Application Note 7 V1.3, 2008-05 CoolMOS™ 900V New 900V class for superjunction devices A new horizon for SMPS and renewable energy applictions 2 Device characteristics CoolMOSTM 900V is the next step towards THE IDEAL HIGH VOLTAGE SWITCH with key features: ✓ Very low conduction and switching losses ✓ Lowest on-state-resistance per package @ 900 V blocking capability ✓ Ultra-low gate charge and lowest figure-of-merit RDS(on) x Qg … which gives the application benefits: ✓ Extremely reduced heat generation ✓ Reduced system size and weight ✓ Very low gate drive power facilitating the use of low cost ICs and gate drivers ✓ Reduced overall system cost The most interesting circuit design aspect is that the more than square-law dependency of the area-specific onresistance (RDS(on) x A) on the breakdown voltage in the case of standard MOSFETs has been amended and a close to linear proportionality has been achieved: RDS ( on ) ⋅ A ∝ (VBr ) n 2,4...2,6 Standard MOS n= TM Cool MOS 1,3 It follows from this that the on-state losses Pstat present in the switch when transferring a particular power are: 2 2 Pstat ∝ I sw,eff ⋅ RDS ( on ) ∝ Pout ⋅ VBr n −2 Therefore, whereas the losses increase with the operating voltage when using a standard MOSFET(proportional to V 0,4…0,6 ), the losses are reduced using CoolMOS™ transistors proportionally to V -0,7. CoolMOSTM 900V series has the world’s lowest area-specific RDS(on) for 900V MOSFETs as shown Figure 4, which results in lowest RDS(on) per package type. 120mΩ in TO247 and 340mΩ in TO220 result in low conduction losses and high current handling capability. Continuous drain currents up to 36A and pulse currents up to 96A are possible (CoolMOS™ 900V 120mΩ). A comparison of available RDS(on)-values in DPak, TO220 and TO247 are given in Figure 4. 8 1.4 5 4 3 2 1.2 1 0.8 0.6 0.4 1 0.2 0 0 D-Pak Figure 4 Other 900V MOSFET 1 Other 900V MOSFET 2 Other 900V MOSFET 3 CoolMOS™ 900V 1.6 RDSon [Ohm] 6 RDSon [Ohm] 1.8 Other 900V MOSFET 1 Other 900V MOSFET 2 Other 900V MOSFET 3 CoolMOS™ 900V 7 TO-220 TO-220 TO-247 TO-247 Comparison of RDS(on),max for best-in-class 900V devices (Right: Zoom-in TO220/TO247) Application Note 8 V1.3, 2008-05 CoolMOS™ 900V New 900V class for superjunction devices A new horizon for SMPS and renewable energy applictions The CoolMOS™ 900V cuts down the achievable RDS(on) in both packages by nearly a factor of four. By introducing our new CoolMOS™ 900V technology we establish also a reduction of the total gate charge. The new technology reduces the total gate charge Qg for similar RDS(on) types by 25% (Figure 5) and offers the lowest FOM (RDS(on) x Qg) in this voltage class. The FOM on the one hand a measure of the conduction losses attributed to the switch, on the other hand it correlates with the Qg a parameter being related to the energy the driver circuit has to offer to turn the switch on and off. A very low FOM stands therefore for low conduction losses, easy driving and low switching losses. 80 100 70 Other 900V MOSFET 1 Other 900V MOSFET 2 60 Other 900V MOSFET 3 Other 900V MOSFET 4 90 Qg*RDSon [Ohm*nC] Qg [nC] CoolMOS™ 900V 50 40 30 20 80 70 Other 900V MOSFET 1 Other 900V MOSFET 2 Other 900V MOSFET 3 Other 900V MOSFET 4 60 50 40 30 20 10 10 0 0 Figure 5 CoolMOS™ 900V Gate Charge QG and Figute-of-merit (RDS(on) x QG) values for 900V devices with nearly same RDS(on) of 1.3-1.4Ω Not only has the new technology achieved breakthrough at reduced RDS(on) values, but new benchmarks have also been set for the device capacitances. A second effect to be considered in the switching losses is the energy being stored in the output capacitance. This energy Eoss (Figure 6) is transfered into heat during hard switched turn-on. Due to the strongly nonlinear voltage dependence of the output capacitance the 900V CoolMOS™ compensation devices offer here a very good performance if switched to more than 150V (marked in Figure 6). Eoss [µJ] Energy stored in the output capacitance of the MOSFETs is reduced by a factor of two or more at working voltage. 8 7 6 5 4 3 2 1 0 Other 900V MOSFET 1 Other 900V MOSFET 2 Other 900V MOSFET 3 Other 900V MOSFET 4 CoolMOS™ 900V 0 Figure 6 100 200 300 VDS [V] 400 500 Eoss values for different 900V MOSFETs Application Note 9 V1.3, 2008-05 CoolMOS™ 900V New 900V class for superjunction devices A new horizon for SMPS and renewable energy applictions Target applications CoolMOSTM 900V 3 The new CoolMOSTM 900V serie offers more design flexibility and pushes the existing limits towards higher power without significant disadvantages. Designers of power units benefit from the high blocking voltage, low RDS(on) and low Gate charge of the new CoolMOSTM 900V. Some examples are explained in the following paragraphs. 3.1 Wide range designs (90…270Vac) with their typical 400Vdc bulk voltage Designs for standard grid voltages can benefit from the higher blocking voltage. Depending on the application the efficiency can be increased and/or design can be simplified without additional costs or other disadvantages. Example 1: 500W Single Transistor Forward (STF) Converter used in ATX power supplies Major benefits with CoolMOSTM 900V: • 500W output power achievable with STF • higher efficiency (+0.7% with BiC TO220) • lower cost and part count • easier design (no high side control) compared to TTF The output power benchmark for STF converters can be increased by using CoolMOSTM 900V. Up to 500W is achievable with a single MOSFET with increased performance and lower costs compared to standard TwoTransistor-Forward (TTF) with 200mΩ 500V/600V MOSFETs. Figure 7 shows the schematics of both topologies. In the STF we have only one transistor compared to the two transistors and the pulse transformer in a TTF. TTF Figure 7 STF ATX power supplies (secondary side schematic being simplified). Application Note 10 V1.3, 2008-05 CoolMOS™ 900V New 900V class for superjunction devices A new horizon for SMPS and renewable energy applictions Changing the topology from TTF to STF not only simplifies the design and adds layout benefits without the disadvantages (like the need of high-side-switching) of TTF. Table 2 shows a comparison of the primary side losses of TTF and STF. Working frequency is 100kHz. Table 2 Losses comparison Two-Transistor-Forward vs. Single-Transistor-Forward Converter TTF with 200mΩ/600V STF with 500mΩ/900V STF with 340mΩ/900V Conduction 6.5W 8.1W 5.5W Output capacitance 2.8W 1.0W 2.1W Switching 7.3W 4.7W 4.7W --- 0.5W 0.5W 16.6W 14.3W 12.8W Losses Demagnetizing winding Total losses Despite the higher RDS(on) of the CoolMOSTM 900V it is possible to design a STF with a higher efficiency than a TTF with 200mΩ 600V MOSFETs. This is due to the higher dynamic losses in a TTF because in every cycle two transistors have to be switched compared to only one transistor in a STF. Indeed the transformer in a STF needs an additional demagnetizing winding which causes a small amount of losses which do not exist in TTF topology. But with careful design (bifilar winding) these losses can be very low and don´t influence the result significant. Cost optimized designs use the 500mΩ CoolMOSTM 900V with slightly increased efficiency (compared to TTF with 200mΩ MOSFETs) and reducing losses up to 0.7% is possible using the 340mΩ CoolMOSTM 900V. Application Note 11 V1.3, 2008-05 CoolMOS™ 900V New 900V class for superjunction devices A new horizon for SMPS and renewable energy applictions Example 2: 200W Quasiresonant Flyback converters for LCD-TV Major benefits with CoolMOSTM 900V: • more than 200W of output power achievable with Quasi-Resonant Flyback • improved EMI behavior due to true zero-voltage switching • higher efficiency (+0.7% compared to 600V or 650V parts, 0.2% compared to 800V parts) • lower voltage stress on secondary diodes or synchronous rectifiers Modern LCD-TV require output power up to 200W with high efficieny of the power supply together with low costs. The best topology for these requirements is the Quasi-Resonant Flyback Converter (QR-FB) and its disadvantages (like the high peak voltage on primary switch) are easy to handle with CoolMOSTM 900V. Figure 8 Quasi-Resonant Flyback Converter for LCD-TV (schematic simplified on secondary) MOSFETs with high blocking voltage allow optimized transformer design resulting in reduced semiconductor losses and reduced voltage stress on secondary diode or synchronous rectifier. Efficiency improvement of 0.2% compared to availabe 800V parts and even 0.7% compared to standard 650V parts is possible using CoolMOSTM 900V. Table 3 shows the results of a 200W / 24V Quasiresonant Flyback design realized with 650V, 800V and 900V MOSFETs, respectively at a switching frequeny of 100kHz Application Note 12 V1.3, 2008-05 CoolMOS™ 900V New 900V class for superjunction devices A new horizon for SMPS and renewable energy applictions Table 3 200W / 24V Quasiresonant Flyback with different types of MOSFETs Benefit by using CoolMOS™ 900V 650V 500mΩ CoolMOS 800V 500mΩ CoolMOS 900V 500mΩ CoolMOS Duty Cycle at Vin,min and max load 18% 27% 32% Longer DC tue to higher reflected voltage Peak current 4.8 A 3.1 A 2.7 A Reduced peak current Conduction losses 1.35 W 0.90W 0.76 W Reduced conduction loss Turn-on-losses 0.17 W 0.09 W 0 True zero-voltage switching! Æ Improved EMI behaviour! Turn-off-losses 1.4 W 0.9 W 0.8 W Reduced turn-off loss due to lower peak current Voltage stress on secondary side diode 91 V 57V 48V Reduced voltage stress on sec. side diode or sync.rec MOSFET Total losses 6.6 W 5.6 W 5.2 W Efficiency loss 3.31 % 2.80 % 2.61 % Application Note 13 Significant loss reduction! 0.7% vs. 650V 0.2% vs. 800V V1.3, 2008-05 CoolMOS™ 900V New 900V class for superjunction devices A new horizon for SMPS and renewable energy applictions 3.2 Replacement of IGBTs by CoolMOS™ 900V Series Using a MOSFET with its Ohmic forward characteristic allow a significant reduction of conduction losses below the power dissipation of IGBTs where conduction losses can not fall below the on-set voltage times load current. PFC and PWM stages are possible to up to 750V bulk voltage using CoolMOSTM 900V without diminishing safety margin. Example 3: Renewable energy applications / solar converters TM Major benefits with CoolMOS 900V: • more panels in series possible→lower copper losses in wiring • higher overall efficiency • no Overvoltage Protection (OVP) necessary • smaller magnetic components due to higher switching frequency Figure 9 Typical DC / AC Solar Converter (with Overvoltage Protection) Renewable energy applications such as photovoltaic converters show very high efficiency requirements due to system amortization via pay back of electricity fed back into the public network. The use of MOSFETs instead of IGBTs enhances the efficiency especially in the mid range of output power - as being characteristic especially for many days in central and Northern Europe – by avoiding the characteristic onset voltage of the IGBT. The clear disadvantage of the MOSFET, its limited blocking voltage range and its more than square-law between RDS(on) and BVDSS is amended by the new MOS generation CoolMOSTM 900 V. This new product family allows to build converters with an enlarged input voltage range coming thus closer to the upper limit of 1000 V as defined by the IEC 60364 for solar modules. Putting more panels in series instead of paralleling reduces significantly cabling losses, efforts and costs. Alone the cabling losses can be cut by factor of 2 when changing from 600 to 900 V voltage class. Another factor in photovoltaic systems is size and cost of magnetic components. Offering a device with improved RDS(on) x Qg and RDS(on) x Eoss performance allows an increase of switching frequency without suffering from the penalty of increased losses. Therefore reduction of system size is possible without losing energy efficiency. Application Note 14 V1.3, 2008-05 CoolMOS™ 900V New 900V class for superjunction devices A new horizon for SMPS and renewable energy applictions 3.3 Lighting applications Using SEPIC topology as PFC converter eliminates high inrush current and improve surge current capability. With CoolMOSTM 900V the necessary higher blocking voltage compared to standard PFC boost topology can be handled. Figure 10 Lamp ballast with SEPIC preconverter Additionally the 3-Phase-Supply of Lamp ballasts for street lighting and greenhouses requires a higher voltage capability than is offered with 600V or 800V MOSFETs, and lower on-resistance than what is offered with conventional 900V MOSFETs. Ballasts for Flat Fluorescent Lamps require switches with a higher voltage capability due to the favored single switch resonant topology. 3.4 Auxiliary power supplies in 3-phase systems Using a 3-phase grid the blocking voltage of the MOSFETs in auxiliary power supplies needs to be higher than 800V. With CoolMOSTM 900V Flyback converters even for higher output power levels are easy to design thanks to low conduction, switching and driving losses. Figure 11 Flyback Converter for auxiliary power supplies Application Note 15 V1.3, 2008-05 CoolMOS™ 900V New 900V class for superjunction devices A new horizon for SMPS and renewable energy applictions 4 Product Portfolio CoolMOSTM 900V portfolio in Figure 12 will be filled up during 2008. Figure 12 CoolMOSTM 900V Products. Figure 13 Naming System for CoolMOSTM Products Application Note 16 V1.3, 2008-05 CoolMOS™ 900V New 900V class for superjunction devices A new horizon for SMPS and renewable energy applictions 5 Circuit Design and Layout Recommendations There are a number of recommendations to make with respect to circuit design and layout practices which will assure a combination of high performance and reliability. They can be recommended as if “in order of importance”, but realistically all are important, both in contribution toward circuit stability and reliability as well as overall efficiency and performance. They are not that dissimilar to recommendations made for the introduction of MOSFETs compared to bipolar transistors, or CoolMOSTM compared with standard MOSFETs; it is a matter of the degree of care. 5.1 Control dv/dt and di/dt by Proper Selection of Gate Resistor In order to exert full Rg control on the device maximum turn-off dv/dt we recommend the following procedure: 1) Check for highest peak current in the application 2) Choose Rg accordingly not to exceed 50 V/ns (maximum rating in datasheet) 3) At normal operation condition quasi ZVS condition can be expected, which gives best efficiency results 5.2 Minimize Parasitic Gate-Drain Board Capacitance Particularly care must be spent on the coupling capacitances between gate and drain traces on the PCB. As fast switching MOSFETs are capable to reach extremely high dv/dt values any coupling of the voltage rise at the TM drain into the gate circuit may disturb proper device control via the gate electrode. As the CoolMOS series reaches extremely low values of the internal Cgd capacitance (Crss in datasheet), we recommend keeping layout coupling capacitances below the internal capacitance of the device to exert full device control via the gate circuit. Figure 14 shows a good example, where the gate and drain traces are either perpendicular to each other or go into different directions with virtually no overlap or paralleling to each other. A “bad“ layout example is shown as reference to the good layout in Figure 15. If possible, use source foils or ground-plane to shield the gate from the drain connection. Two independent Totem Pol Drivers as close as possible to the MOSFET! View Top Layer View Bottom Layer Heatsink Heatsink Separate and short source inductance to reference point for gate drive! Figure 14 Minimized couple capacitance between gate and drain pin! Heatsink is connected to source (GND)!! Good Layout Example Ensuring Clean Waveforms When Designing in CoolMOSTM Application Note 17 V1.3, 2008-05 CoolMOS™ 900V New 900V class for superjunction devices A new horizon for SMPS and renewable energy applictions Decoupling capacitor far away from gate pin of the MOSFET & ONLY One Driver Stage for two MOSFET High source inductance - GND connection of the decoupling capacitor C2 far away from the driver stage Heatsink High parasitic capacitance between gate and drain! Figure 15 5.3 Bad Layout Example Locate Gate Drivers and Gate Turn-Off Components as Close as Possible to the Gate Always locate the gate drive as close as possible to the driven MOSFET and the gate resistor in close proximity of the gate pin. This prevents it acting as an antenna for capacitively coupled signals. The controller/IC driver should be capable of providing a strong “low” level drive with voltage as near to ground as possible- MOS or bipolar/MOS composite output stages work well in that regard, due to low output saturation voltages. While some drivers may be deemed to have sufficient margin under static or “DC” conditions, with ground bounce, source inductance drop, etc, the operating margin to assure “off” mode can quickly disappear. 5.4 Use Symmetrical Layout for Paralleling MOSFETs, and Good Isolation of Gate Drive between FETs We recommend the use of multi-channel gate drivers in order to have separate channels for each MOSFET. Physical layout should be as symmetrical as possible, with the low impedance driver located as close as possible to the MOSFETs and on a symmetric axis. 5.5 Summary To summarize, below recommendations are important when designing in CoolMOSTM 900V to reach highest efficiency with clean waveforms and low EMI stress. ✓ Control dv/dt and di/dt by proper selection of gate resistor ✓ Minimize parasitic gate-drain capacitance on board ✓ Locate gate drivers and gate turn-off components as close as possible to the gate ✓ Use symmetrical layout for paralleling Application Note 18 V1.3, 2008-05 CoolMOS™ 900V New 900V class for superjunction devices A new horizon for SMPS and renewable energy applictions References [1] T. Fujihira: “Theory of Semiconductor Superjunction Devices”, Jpn.J.Appl.Phys., Vol. 36, pp. 62546262, 1997. [2] A.W. Ludikhuize, “A review of the RESURF technology”, Proc. ISPSD 2000, pp. 11-18. [3] X. B. Chen and C. Hu, “Optimum doping profile of power MOSFET’s epitaxial Layer”, IEEE Trans. Electron Devices, vol. ED-29, pp. 985-987, 1982. [4] G. Deboy, M. März, J.-P. Stengl, H. Strack, J. Tihanyi, H. Weber, “A new generation of high voltage MOSFETs breaks the limit of silicon”, pp. 683-685, Proc. IEDM 98, San Francisco, Dec. 1998. Application Note 19 V1.3, 2008-05 www.infineon.com Published by Infineon Technologies AG