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 2
On-State Resistance (R DS-ON )& Body Diode Schematic • Same schematic, different settings • R DS-ON gate input=10V • Body diode gate input=0V • Polarity changes opposite current paths
On-State Resistance Results (Infineon) Curve Tracer Results 1.20E+02 • Curve Tracer plots are 1.00E+02 used to calculate the on-state resistance. 8.00E+01 Drain Current (A) • Use rated current and 25 C 0 C corresponding voltage 6.00E+01 -30 C -60 C -90 C -120 C 4.00E+01 -150 C -180 C 2.00E+01 0.00E+00 0.00E+00 5.00E+00 1.00E+01 1.50E+01 2.00E+01 Drain Source Voltage (V) 4
On-State Resistance Cont. Temperature Effect 0.18 • Calculated on-state resistance using previous 0.16 plot at different On-State Resistance (Ω) 0.14 temperatures. 0.12 • R DS-ON = V DS /I RATED 0.1 0.08 0.06 0.04 0.02 0 -2.00E+02-1.50E+02-1.00E+02-5.00E+01 0.00E+00 5.00E+01 Temperature (C)
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) 100 90 80 70 60 Id(A) 50 40 30 20 10 0 0 0.5 1 1.5 2 2.5 Vsd(V)
Switching Losses Schematic Cryo. Chamber + – DC Upper Load source Diode Inductor DC Link Capacitor Scope AUX Power Power Supply Supply Signal Gate Lower Signal Isolator/ Driver Switch Generator Logic
Switching Losses Cont. • 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 Energy Losses Curve (Infineon) 30 20A 20A 25 20 Esw(uJ) 10A 10A 15 3A 3A 10 5 0 0 50 100 150 200 250 300 350 Temperature(K)
Breakdown Voltage Ampere meter • High voltage applied; near the rated A voltage of the device • Current = 1mA is considered Cryo. chamber breakdown for the device. D Device + • Gate and source shorted High voltage • 100 kOhms resistor under – DC source G test (DUT) S Current limiting resistor
750 Breakdown Voltage 700 Results Breakdown Voltage(V) 650 • The Drain-Source Voltage • Determined by reverse breakdown behavior 600 • Reduces as temperature decreases 550 500 450 70 120 170 220 270 320 Temperature(K)
Conclusion Efficiency of MOSFET devices improves at cryogenic operation: • Faster switching w/ less losses • Allows larger current with less overshooting • 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 15
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