Power Diodes for Cryogenic Operation

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Power Diodes for Cryogenic Operation

• PESC 2003

Acapulco, Mexico, June 2003
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R. R. Ward, W. J. Dawson, L. Zhu, R. K.
Kirschman GPD Optoelectronics Corp., Salem, New
Hampshire O. Mueller, M. J. Hennessy, E. K.
Mueller LTELow Temperature Electronics,
Ballston Lake, New York R. L. Patterson,
J. E. DickmanNASA Glenn Research Center,
Cleveland, Ohio A. HammoudDynacs Corp.,
Cleveland, Ohio
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Motivation
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Cryogenic Power Electronics

• Semiconductor devices (diodes and transistors)
• For Power Management and Actuator Control
• For use down to 30 K 243C (and lower)
• Supported by NASA Glenn Research Center

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Very Little of the Solar System (or the
Universe) Is at Room Temperature.
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Solar System Temperatures
Room Temperature
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ApplicationsSpace

• Solar-system exploration
• Reasons Cold environment, reduced power
• For Outer planets, cold satellites, asteroids,
  interstellar
• Scientific spacecraft/observatories
• Reason Cryogenic sensors and optics
• For Motors and actuators

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ApplicationsDefense, Industry, Commercial

• Medical instruments (MRI)
• Electrical power (superconducting electrical
  power storage, transmission, distribution)
• Motors/generators (superconducting or
  cryogenic)
• Magnetic confinement (superconducting or
  cryogenic)
• High-power amplifiers (cell phone base stations,
  MRI)

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ApplicationsDefense, Industry, Commercial

• Medical instruments (MRI)
• Electrical power (superconducting electrical
  power storage, transmission, distribution)
• Motors/generators (superconducting or
  cryogenic)
• Magnetic confinement (superconducting or
  cryogenic)
• High-power amplifiers (cell phone base stations,
  MRI)
• Reasons Improved efficiency and reliability,
  reduced size and mass many systems already
  incorporate cryogenics

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ApplicationsSpace

• Solar-system exploration
• Reasons Cold environment, reduced power
• For Outer planets, cold satellites,
  interstellar
• Scientific spacecraft/observatories
• Reason Cryogenic sensors and optics
• For Motors and actuators

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Spacecraft
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Spacecraft
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Spacecraft
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Cold Spacecraft

• Eliminate heating, thermal control, isolation
• Reduce power, weight, size, cost, complexity
• Improve overall reliability
• Reduce disruption of environment
• Increase mission duration capability

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ApplicationsSpace

• Solar-system exploration
• Reasons Cold environment, reduced power
• For Outer planets, cold satellites,
  interstellar
• Scientific spacecraft/observatories
• Reason Cryogenic sensors and optics
• For Motors and actuators

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Why use Ge?
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Why Ge Devices?

• Ea,d (Ge) lt Ea,d (Si)

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Why Ge Devices?

• Ea,d (Ge) lt Ea,d (Si) ? Ge can operate at lower T

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Why Ge Devices?

• Ea,d (Ge) lt Ea,d (Si) ? Lower T for Ge
• Experience with Ge JFETs at cryogenic temperatures

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Why Ge Devices?

• Ea,d (Ge) lt Ea,d (Si) ? Lower T for Ge
• Experience with Ge JFETs at cryogenic
  temperatures
• Ge has advantages over other semiconductor
  materials
• ? Higher mobility than Si (especially at low
  temp)
• Lower p- n junction forward voltage than Si or
  III-Vs

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Mobility Comparison
Data from Madelung, 1991, pp. 18,34.
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Why Ge Devices?

• Ea,d (Ge) lt Ea,d (Si) ? Lower T for Ge
• Experience with Ge JFETs at cryogenic
  temperatures
• Ge has advantages over other semiconductor
  materials
• Higher mobility than Si (especially at low temp)
• ? Lower p- n junction forward voltage than Si or
  III-Vs

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P-N Junction (Diode) Forward Voltage
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Why Ge Devices ? (contd)

• Applications require operation to 30 - 40 K range
• Ge devices of all types can operate to low
  cryogenic temperatures ( 20 K or lower)
• ? Diodes can operate to deep cryogenic
  temperatures
• JFETs can operate to deep cryogenic temperatures
  (down to few K)
• Bipolar transistors can operate to deep
  cryogenic temperatures

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Commercial 15-A Ge Diode
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Commercial 15-A Ge Diode
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Commercial 60-A Ge Diode
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Commercial 60-A Ge Diode
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Why Ge Devices? (contd)

• Applications require operation to 30 - 40 K range
• Ge devices of all types can operate to low
  cryogenic temperatures ( 20 K or lower)
• Diodes can operate to deep cryogenic temperatures
• ? JFETs can operate to deep cryogenic
  temperatures (down to few K)
• Bipolar transistors can operate to deep
  cryogenic temperatures

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Field-Effect Transistor Comparison
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Ge JFET at 20 K (253ºC)
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Ge MISFET at 4 K (273ºC)
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Why Ge Devices? (contd)

• Applications require operation to 30 - 40 K range
• Ge devices of all types can operate to low
  cryogenic temperatures ( 20 K or lower)
• Diodes can operate to deep cryogenic temperatures
• JFETs can operate to deep cryogenic temperatures
  (down to few K)
• ? Bipolar transistors can operate to deep
  cryogenic temperatures (down to 20 K or
  lower)

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Ge Bipolar Junction Transistor
300 K
4 K
Zero upper right Horiz 0.5 V/div Vert
1 mA/div IB 0.02 mA/step at RT, 0.1 mA/step at 4
K
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Ge Bipolar Junction Transistor
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Bipolar Junction Transistor Comparison
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Results for New Ge Diodes
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New Planar Ge Cryo Power Diodes
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New Ge Cryo Power Diodes - Forward
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New Ge Cryo Power Diodes - Forward
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Ge Power Diodes - Forward Voltage
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Ge Power Diodes - Forward Voltage
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Ge Power Diodes - Reverse Breakdown
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Ge Power Diodes - Reverse Recovery
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Ge Power Diodes - Reverse Recovery
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Ge Power Diodes - Reverse Recovery
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Ge Power Diodes - Reverse Recovery
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Ge Power Diodes - Reverse Recovery
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Summary

• Cryogenic power electronics is needed for
  spacecraft going to cold environments and for
  space observatories
• Temperatures may be as low as 30 - 40 K
• We have characterized Ge devices diodes,
  JFETs, and bipolars at cryogenic temperatures
• Ge devices can operate to deep cryogenic
  temperatures to 20 K and as low as 4 K
• We are developing Ge diodes specifically for
  cryogenic applications