Sic a new era in power electronics


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Sic a new era in power electronics

  1. 1. SIC- A NEW ERA INPOWERELECTRONICSPrepared By:Krunal P. Siddhapathak (10bec097)
  2. 2. OUTLINE Introduction Why used in high temperature application? Advantages Applications Why SiC is not used? Conclusion
  3. 3. INTRODUCTION Silicon Carbide (SiC) is a very hard semiconductor material SiC has been used in abrasive products such as grindingwheels for more than one hundred years. Today, high quality monocrystal SiC substrates withdiameters up to 100 mm are commercially available and theirmain application is light-emitting diodes. SiC is becoming more widely used in power applicationssuch as power factor control in power supplies. SiC has a wide band gap of 3.2 eV which is almost three timesthe band gap of Si (1.1 eV). This quality enables semiconductor devices made out of thismaterial to maintain a satisfactory function even at highertemperatures.
  4. 4. INTRODUCTION(CONTD.) Silicon Carbide’s wide band gap makes it possible to producepower transistors that block high voltages and have low seriesresistance, leading to low conduction losses. Thanks to the low conduction losses, the chip size canbe reduced and it is possible to switch the transistors with lowswitching losses. The high band gap also enables power transistors to switchhigh voltage and current at high temperatures. In conclusion, SiCs power transistors are electricallyrobust, with excellent short circuit capabilities.
  5. 5. Fig 1 Schematic of hetrojunction SiCtransistor
  6. 6. WHY SIC IS USED IN HIGHTEMPERATURE APPLICATIONS? The variation in current gainversus temperature is shownin figure As shown in figure there isonly 10 to 15% change incurrent gain whentemperature changes from300K to 400K. While normal transistor failat elevated temperature dueto significance increase incurrent gain.
  7. 7. ADVANTAGES Higher Power Density Through higher switching frequency at same or lowerlosses, enabling the use of smaller inductors, heat-sink andcapacitors Increase output power while maintaining system formfactor Lower System Cost Through lower losses and higher power density, smallercooling and increased power output for the same hardware Offer productivity improvement.
  8. 8. ADVANTAGES(CONTD.) Key SiC Features Wide band gap (3.2 eV, 3x Si) High break down field (2.4 MV/cm, 10x Si) High thermal conductivity (4 W/cm K, 3x Si) High temperature stability. Fast Switching Approximately 20 ns for turn-on and turn-off. Switching behaviour is not temperature dependant. No current tailing for SiC BJT.
  9. 9. ADVANTAGES(CONTD.) Robust and Reliable Normally OFF device. Highest rated operating temperature =175 C Positive temperature coefficient (Ron) No Secondary breakdown for SiC BJT Low leakage current. Short circuit resistance. No SiO2 gate oxide reliability issue.
  10. 10. APPLICATIONS High Efficiency Applications such as renewableenergy, industrial systems and mobile power all require highefficiency, small size and light weight. Fairchild is developing a series of device solutions that willoffer the industry’s highest efficiency compared to any othertransistors available today. These components also eliminate many of the size, weight andtemperature trade-offs associated with efficiency gains insilicon devices. High Temperature The ability for power semiconductors toprovide reliable operation at high temperatures.
  11. 11. APPLICATIONS(CONTD.) Lower Losses, Faster Switching, Higher PowerDensity Solar inverters Welding systems Mobile power DC-DC converters DC-AC inverters PFC input stages Motor drives
  12. 12. APPLICATIONS(CONTD.) Higher Operating Temperatures High temp DC converters High temp actuator controls High temp motor drivers Motor and turbine controls Surveillance
  13. 13. WHY SILICON CARBIDE DEVICESARE NOT AVAILABLE? Lack of suitable substrate for the industrial scalefabrication of power semiconductor devices. SiC can not be melted under controllable conditions It changes its state directly from solid to gaseous.
  14. 14. CONCLUSION Silicon carbide transistors has several advantages over silicontransistor like fast switching, high power reliability, hightemperature stability etc. Main disadvantages is that lack of substrate in fabrication ofpower semiconductor devices.
  15. 15. REFERENCES B.J.Baliga, “The Future of Power Semiconductor DeviceTechnology”, Proceedings of the IEEE, June2001,Vol.89, No.6, pp.822-832 Orellana Alavaro, Piepenbreier Bernhard, “Fast Gate Drivefor SiC-JFET using a Conventional Driver for MOSFETs andAdditional Protections,” The 30th annual Conference of theIEEE Industrial Electronics Society, pp. 938-943.