1. SIC- A NEW ERA IN
POWER
ELECTRONICS
Prepared By:
Krunal P. Siddhapathak (10bec097)

2. OUTLINE
 Introduction
 Why used in high temperature application?
 Advantages
 Applications
 Why SiC is not used?
 Conclusion

3. INTRODUCTION
 Silicon Carbide (SiC) is a very hard semiconductor material
 SiC has been used in abrasive products such as grinding
wheels for more than one hundred years.
 Today, high quality monocrystal SiC substrates with
diameters up to 100 mm are commercially available and their
main application is light-emitting diodes.
 SiC is becoming more widely used in power applications
such as power factor control in power supplies.
 SiC has a wide band gap of 3.2 eV which is almost three times
the band gap of Si (1.1 eV).
 This quality enables semiconductor devices made out of this
material to maintain a satisfactory function even at higher
temperatures.

4. INTRODUCTION(CONTD.)
 Silicon Carbide’s wide band gap makes it possible to produce
power transistors that block high voltages and have low series
resistance, leading to low conduction losses.
 Thanks to the low conduction losses, the chip size can
be reduced and it is possible to switch the transistors with low
switching losses.
 The high band gap also enables power transistors to switch
high voltage and current at high temperatures.
 In conclusion, SiC's power transistors are electrically
robust, with excellent short circuit capabilities.

5. Fig 1 Schematic of hetrojunction SiC
transistor

6. WHY SIC IS USED IN HIGH
TEMPERATURE APPLICATIONS?
 The variation in current gain
versus temperature is shown
in figure
 As shown in figure there is
only 10 to 15% change in
current gain when
temperature changes from
300K to 400K.
 While normal transistor fail
at elevated temperature due
to significance increase in
current gain.

7. ADVANTAGES
 Higher Power Density
 Through higher switching frequency at same or lower
losses, enabling the use of smaller inductors, heat-sink and
capacitors
 Increase output power while maintaining system form
factor
 Lower System Cost
 Through lower losses and higher power density, smaller
cooling and increased power output for the same hardware
 Offer productivity improvement.

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. 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. APPLICATIONS
 High Efficiency Applications such as renewable
energy, industrial systems and mobile power all require high
efficiency, small size and light weight.
 Fairchild is developing a series of device solutions that will
offer the industry’s highest efficiency compared to any other
transistors available today.
 These components also eliminate many of the size, weight and
temperature trade-offs associated with efficiency gains in
silicon devices.
 High Temperature The ability for power semiconductors to
provide reliable operation at high temperatures.

11. APPLICATIONS(CONTD.)
 Lower Losses, Faster Switching, Higher Power
Density
 Solar inverters
 Welding systems
 Mobile power
 DC-DC converters
 DC-AC inverters
 PFC input stages
 Motor drives

12. APPLICATIONS(CONTD.)
 Higher Operating Temperatures
 High temp DC converters
 High temp actuator controls
 High temp motor drivers
 Motor and turbine controls
 Surveillance

13. WHY SILICON CARBIDE DEVICES
ARE NOT AVAILABLE?
 Lack of suitable substrate for the industrial scale
fabrication of power semiconductor devices.
 SiC can not be melted under controllable conditions
 It changes its state directly from solid to gaseous.

14. CONCLUSION
 Silicon carbide transistors has several advantages over silicon
transistor like fast switching, high power reliability, high
temperature stability etc.
 Main disadvantages is that lack of substrate in fabrication of
power semiconductor devices.

15. REFERENCES
 B.J.Baliga, “The Future of Power Semiconductor Device
Technology”, Proceedings of the IEEE, June
2001,Vol.89, No.6, pp.822-832
 Orellana Alavaro, Piepenbreier Bernhard, “Fast Gate Drive
for SiC-JFET using a Conventional Driver for MOSFETs and
Additional Protections,” The 30th annual Conference of the
IEEE Industrial Electronics Society, pp. 938-943.