Title: SiGe Semiconductor Devices for Cryogenic Power Electronics III
1SiGe Semiconductor Devices for Cryogenic Power
Electronics III
- IMAPS Advanced Technology Workshop on Reliability
of Advanced Electronic Packages and Devices in
Extreme Cold Environments
Pasadena, 21-23 February 2005
2Outline
- The Team and Coordination
- Goals Applications
- Technical Objectives Approach
- SiGe Cryo Power HBTs
- SiGe Cryo Power Converters
- Summary Plans
3The Team
R. R. Ward, W. J. Dawson, L. Zhu, R. K.
Kirschman GPD Optoelectronics Corp., Salem, New
Hampshire G. Niu, R. M. Nelms Auburn University,
Dept. of Electrical and Computer Engineering,
Auburn, Alabama O. Mueller, M. J. Hennessy, E.
K. Mueller MTECH Labs./LTE, Ballston Lake, New
York R. L. Patterson, J. E. Dickman NASA Glenn
Research Center, Cleveland, Ohio A. Hammoud QSS
Group Inc., Cleveland, Ohio
4Coordination
NASA SBIR Phase I and II DARPA STTR Phase I
5Outline
- The Team and Coordination
- Goals Applications
- Technical Objectives Approach
- SiGe Cryo Power HBTs
- SiGe Cryo Power Converters
- Summary Plans
6Overall Goal
- Semiconductor devices (diodes and transistors)
- For power management and distribution (PMAD)
- Electrical power storage and transmission
- Power conversion for motors/generators
- For superconducting or cryogenic systems
- Temperatures down to 20 K
7NASA Interest
- Cryogenic systems for spacecraft/aerospace
- Cold Solar System sites
- Fly-by, orbiting, landers, rovers, penetrators,
... - Propulsion systems
- Power generation/storage/distribution systems
8Solar System Temperatures
9Temperatures for Spacecraft
10Specific NASA Technical Goals
- Demonstrate SiGe devices at cryogenic
temperatures, down to 20 K - Device types SiGe HBTs, MOSFETs, IGBTs
- Demonstrate SiGe superiority over Si devices for
cryogenic power circuits
11Coordination
Separate STTR Program from DARPA Phase I, June -
December 2004 with Auburn University
12Coordination Goals
13Outline
- The Team and Coordination
- Goals Applications
- Technical Approach
- SiGe Cryo Power HBTs
- SiGe Cryo Power Converters
- Summary Plans
14Why SiGe?
- Incorporate desirable characteristics of Si and
Ge - Can optimize devices for cryogenic applications
by selective use of Ge, Si and SiGe - SiGe provides additional flexibility through
band-gap engineering ( of Ge) - Devices can operate at all cryogenic
temperatures (as low as 1 K if required) - All device types work at cryogenic temperatures
- Diodes
- Field-effect transistors
- Bipolar transistors
- Compatible with standard semiconductor processing
15Materials Comparison
16P-N Junction (Diode) Forward Voltage
17SiGe Bandgap
90 K
G. Theodorou et al., Structural, electronic, and
optical properties of strained SiGe alloys,
Phys Rev B, vo.l 50, pp. 18355-18359, 15 Dec.
1994.
18Outline
- The Team and Coordination
- Goals Applications
- Technical Objectives Approach
- SiGe Cryo Power HBTs
- SiGe Cryo Power Converters
- Summary Plans
19Cryo Power HBT Design Example
20A Cryo Power HBT Die
4 mm
21Cryo Power HBT Characteristics
LN
RT
2 A
1 A
20 V
20 V
?IB 5 mA Gain 75
?IB 0.5 mA Gain 500
22Cryo Power HBT Characteristics
23Outline
- The Team and Coordination
- Goals Applications
- Technical Objectives Approach
- SiGe Cryo Power HBTs
- SiGe Cryo Power Converters
- Summary and Plans
24SiGe Boost Converter Circuit
24 V in
48 V out
Inductor
SiGe diode
Output capacitor
Input capacitor
Load
SiGe HBT
Drive circuit
10 300 K
Switching pulse
25SiGe 100 W Cryo Boost Converter100 kHz, 24 V in,
48 V out
26SiGe 100 W Cryo Boost ConverterBackside
27Cryostat for Measuring ?100 W Circuits(variable
temperature 300 to 20 K)
4
Superinsulation
Cooling channel (inside Cu block)
8
Converter circuitry
Cu thermal mass/mounting block
Electrical feedthru
Stainless steel tubes
GHe vent
LHe vendors dewar
LHe
28Cryostat for Measuring ?100 W Circuits
29100 W SiGe Power Converter in Cryostat
30SiGe 100 W Cryo Boost Converter Performance
31Outline
- The Team and Coordination
- Goals Applications
- Technical Objectives Approach
- SiGe Cryo Power HBTs
- SiGe Cryo Power Converters
- Summary Plans
32Summary
- Cryogenic power conversion is of interest for a
range of applications within NASA and elsewhere. - For cryogenic power conversion, SiGe devices are
potentially superior to devices based on Si or
Ge. - We have begun development of SiGe semiconductor
devices (HBTs and MOSFETs) for cryogenic power
applications. - We have designed, fabricated, and used SiGe HBTs
in power converters operating at cryogenic
temperatures and converting gt100 W.
33Plans
- Improve SiGe HBT characteristics (especially at
cryo temps) - By simulation
- On voltage
- Off breakdown voltage
- Switching speed
- Compare power converter performance at cryogenic
temperatures, comparing SiGe HBTs to Si BJTs - Design, fabricate and use SiGe MOSFETs in
cryogenic power circuits - If practical, fabricate SiGe IGBTs