Presented by: Steve Pytel

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AlGaN/GaN MOSHFET INTEGRATED CIRCUIT POWER
CONVERTER Pytel, Lentijo, Koudymov, Rai, Fatima,
Adivarahan, Chitnis, Yang, Hudgins, Santi, Monti,
Simin, and Asif Khan
Presented by Steve Pytel
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Outline

• Why Gallium Nitride
• Commercial Applications
• AlGaN/GaN MOSHFET Structure
• AlGaN/GaN Driver
• Experimental Results
• Conclusion
• Future Work and Questions

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Outline

• Why Gallium Nitride

• Commercial Applications

• AlGaN/GaN MOSHFET Structure

• AlGaN/GaN Driver

• Experimental Results

• Conclusion

• Future Work and Questions

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Integration of Electrical Engineering Disciplines
Power Electronics
Microelectronics
Merge
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Gallium Nitride Properties

• High breakdown voltage
• VB ? EG5
• EG 3.44 eV
• High electron mobility
• 2D e- Gas (2000 cm2/Vs)
• Bulk GaN (900 cm2/Vs)

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Gallium Nitride Properties

• High saturation velocity
• (? 1.5x107 cm/s)
• Large polarization vector
• Spontaneous polarization
• Piezoelectric polarization
• 2DEG mobility ? 1500 2000 cm2/Vs

?
2D e- Gas
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Gallium Nitride Properties
Comparison Between Common Semiconductor Material
Properties
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Outline

• Why Gallium Nitride

• Commercial Applications

• AlGaN/GaN MOSHFET Structure

• AlGaN/GaN Driver

• Experimental Results

• Conclusion

• Future Work and Questions

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Several Commercial Applications

• High power
• Hybrid vehicles
• Electric ships (ESRDC)
• Satellites
• Medium to low power
• Audio amplifiers
• Power-hardware-in-the-loop processes
• Track higher order harmonics ?high BW devices
  needed

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Power Hardware-in-the-Loop
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Outline

• Why Gallium Nitride

• Commercial Applications

• AlGaN/GaN MOSHFET Structure

• AlGaN/GaN Driver

• Experimental Results

• Conclusion

• Future Work and Questions

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AlGaN/GaN MOSHFET Structure

• MOSFHET Vs. HFET
• Lower gate leakage current
• SiC
• High thermal conductivity
• AlGaN/GaN interface
• Produces 2D e- Gas

2D e- Gas
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AlGaN/GaN MOSHFET Structure

• H-BRIDGE
• 4 AlGaN/GaN MOSHFET switches
• Total device area 1.90 mm x 1.25 mm
• Gate length
• Six 200?m parallel gate fingers
• Total gate length 1.20 mm
• Mounted on .025 AlN substrate
• Silver/Copper ink traces with gold overlay
• Gold wire bonds

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AlGaN/GaN MOSHFET Structure
2 5 cm
2 5 cm
Converter mounts here
0805 Resistor
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AlGaN/GaN MOSHFET Structure
1.90 mm
Drain 2
Gate 2
Gate 4
1.25 mm
Source 2 and Drain 4
Source 4 and Source 3
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Outline

• Why Gallium Nitride

• Commercial Applications

• AlGaN/GaN MOSHFET Structure

• AlGaN/GaN Driver

• Experimental Results

• Conclusion

• Future Work and Questions

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Power Converter Driver

• Requirements
• Isolated
• 5 and -12 V
• Fast (limited to ? 200 kHz)

VGS2 (5 V/div)
.2 ?s/div
VGS4 (5 V/div)
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Outline

• Why Gallium Nitride

• Commercial Applications

• AlGaN/GaN MOSHFET Structure

• AlGaN/GaN Driver

• Experimental Results

• Conclusion

• Future Work and Questions

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Converter Output Results

• Switch 2 under test

VDS2 (20 V/div)
.2 ?s/div
tF 105 ns
tR 95 ns
ILoad (200 mA/div)
VLoad (10 V/div)
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Converter Output Results

• Switch 4 under test

.2 ?s/div
VDD 40 V
VLoad (10 V/div)
tR 96 ns
tF 89 ns
Device 2
RLoad 50 ?
Device 4
VDS4 (20 V/div)
ILoad (200 mA/div)
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Half-Bridge Converter Test
1 ?s/div
VDS4 (20 V/div)
ILoad (200 mA/div)
Device 2
R1 50 ?
2.25 ?F
RLoad 50?
VDD 40 V
2.25 ?F
R2 50 ?
Device 4
VGS4 (5 V/div)
VGS2 (5 V/div)
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Outline

• Why Gallium Nitride

• Commercial Applications

• AlGaN/GaN MOSHFET Structure

• AlGaN/GaN Driver

• Experimental Results

• Conclusion

• Future Work and Questions

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Conclusion

• Designed, fabricated, and tested at the
  University of South Carolina
• Successful experimental results
• GaN is a promising emerging material
• High EG ? High VBD, Low Ron
• High ?e
• High ?S
• High ns
• 2DEG

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Conclusion

• Current collapse
• Field assisted trapping
• Material growth
• Speed limited by driver

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Outline

• Why Gallium Nitride

• Commercial Applications

• AlGaN/GaN MOSHFET Structure

• AlGaN/GaN Driver

• Experimental Results

• Conclusion

• Future Work and Questions

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Future Work

• Design faster driver
• gt 1 MHz
• Inductive load testing
• Modeling along with simulation
• Development of higher quality GaN wafers
• Power hardware-in-the-loop testing