MOSFET Characteristics at Cryogenic Temperatures Juan Avalos - - PowerPoint PPT Presentation

MOSFET Characteristics at Cryogenic Temperatures

Juan Avalos Graduate Mentor: Jingyi Tang Faculty Advisor: Dr. Tolbert

University of Tennessee Knoxville REU CURENT July 14, 2016

• Objective: Determine the semiconductor devices with the least energy

losses to use in the DC-AC inverter for Boeing & NASA aircraft.

• Devices: Microsemi, Infineon, IXYS
• Characteristics:
• On-state resistance
• Body Diode
• Switching Losses
• Breakdown Voltage

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On-State Resistance (RDS-ON)& Body Diode Schematic

• Same schematic, different

settings

• RDS-ON  gate input=10V
• Body diode  gate input=0V
• Polarity changes  opposite

current paths

4

• Curve Tracer plots are

used to calculate the

• n-state resistance.
• Use rated current and

corresponding voltage

0.00E+00 2.00E+01 4.00E+01 6.00E+01 8.00E+01 1.00E+02 1.20E+02 0.00E+00 5.00E+00 1.00E+01 1.50E+01 2.00E+01 Drain Current (A) Drain Source Voltage (V)

Curve Tracer Results

25 C 0 C

• 30 C
• 60 C
• 90 C
• 120 C
• 150 C
• 180 C

On-State Resistance Results (Infineon)

• Calculated on-state

resistance using previous plot at different temperatures.

• RDS-ON= VDS/IRATED

0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18

• 2.00E+02-1.50E+02-1.00E+02-5.00E+01 0.00E+00 5.00E+01

On-State Resistance (Ω) Temperature (C)

Temperature Effect

On-State Resistance Cont.

Body Diode

• Device in cut off region
• Polarity of input is reversed w/

respect to on-state resistance

• Reverse drain current shorts the

source and drain

• High current path created

through body diode

Results of Body Diode (Infineon)

10 20 30 40 50 60 70 80 90 100

0.5 1 1.5 2 2.5

Id(A)

Vsd(V)

Switching Losses Schematic

Load Inductor Upper Diode Lower Switch

– +

DC Link Capacitor Gate Driver DC source Signal Generator Signal Isolator/ Logic AUX Power Supply Scope Power Supply

• Cryo. Chamber

• Double Pulse Test:
• First pulse is used to charge up

inductor current at desired value.

• First Falling edge = turn-off

switching transient

• Second Rising edge = turn-on

switching transient

• Parasitic inductance & capacitance
• Cause ringing and overshoot in

switching transients  losses

Switching Losses Cont.

Switching Energy Losses Curve (Infineon)

5 10 15 20 25 30 50 100 150 200 250 300 350

Esw(uJ)

Temperature(K)

20A 10A 3A 20A 10A 3A

Breakdown Voltage

• High voltage applied; near the rated

voltage of the device

• Current = 1mA is considered

breakdown for the device.

• Gate and source shorted
• 100 kOhms resistor

– +

A

D G S High voltage DC source Current limiting resistor Ampere meter Device under test (DUT)

• Cryo. chamber

Breakdown Voltage Results

• The Drain-Source Voltage
• Determined by reverse breakdown

behavior

• Reduces as temperature

decreases

450 500 550 600 650 700 750 70 120 170 220 270 320

Breakdown Voltage(V) Temperature(K)

Conclusion

Efficiency of MOSFET devices improves at cryogenic operation:

• Faster switching w/ less losses
• Allows larger current with less
• vershooting
• On-state resistance drastically

decreases

Acknowledgements

This work was supported primarily by the ERC Program of the National Science Foundation and DOE under NSF Award Number EEC-1041877. Other US government and industrial sponsors of CURENT research are also gratefully acknowledged. 14

Questions and Answers

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