Post on 02-Jan-2016
Novel SiGe Semiconductor Novel SiGe Semiconductor
Devices forDevices for
Cryogenic Power ElectronicsCryogenic Power Electronics
ICMC/CEC August-September 2005Keystone, Colorado
2
Outline
Authors and Sponsors
Goals and Applications
Why SiGe?
Designs and results
SiGe heterojunction diodes
Cryogenic power converter
Summary
3
Outline
Authors and Sponsors
Goals and Applications
Why SiGe?
Designs and results
SiGe heterojunction diodes
Cryogenic power converter
Summary
4
Rufus Ward, Bill Dawson, Lijun Zhu, Randall Kirschman
GPD Optoelectronics Corp., Salem, New Hampshire
Guofu Niu, Mark Nelms
Auburn University, Dept. of Electrical and Computer
Engineering, Auburn, Alabama
Mike Hennessy, Eduard Mueller, Otward Mueller,
MTECH Labs./LTE, Ballston Lake, New York
Authors
GPD Optoelectronics GPD Optoelectronics CorporationCorporation
5
Sponsors
US Office of Naval Research
US Army Aviation and Missiles Command
Defense Advanced Research Projects Agency
6
Outline
Authors and Sponsors
Goals and Applications
Why SiGe?
Designs and results
SiGe heterojunction diodes
Cryogenic power converter
Summary
7
Goals
• Develop SiGe devices for cryogenic power use
• Exhibit the performance advantages of SiGe versus Si for cryogenic power
• Specifically:
– Demonstrate prototype SiGe power diodes for cryogenic operation
– Demonstrate a 100-W power conversion circuit, to deep cryogenic temperatures.
– To ~ 55 K
8
Application Areas
• For power management and distribution (PMAD)
– Power conversion for storage and distribution
– Power conversion for motors/generators
– E.g. “All-Electric” ship
• DoD applications
– Cryogenic systems for ships and aerospace
– Propulsion systems
– Superconducting or cryogenic
– Temperature ~ 60 – 65 K (for HTSC)
9
Outline
Authors and Sponsors
Goals and Applications
Why SiGe?
Designs and results
SiGe heterojunction diodes
Cryogenic power converter
Summary
10
Why SiGe?• Can incorporate desirable characteristics of both Si and Ge
• Can optimize devices for cryogenic applications by selective use of Si and SiGe
• SiGe provides additional flexibility through band-gap engineering (% of Ge, grading) and selective placement
• All device types work at cryogenic temperatures–
Diodes
– Field-effect transistors– Bipolar transistors– Combinations of above (IGBTs, thyristors, ...)
• Devices can operate at all cryogenic temperatures (as low as ~ 1 K if required)
• Compatible with conventional Si processing
11
Outline
Authors and Sponsors
Goals and Applications
Why SiGe?
Designs and results
SiGe heterojunction diodes
Cryogenic power converter
Summary
12
SiGe Diode Simulations
13
SiGe Heterostructure Diode
(N+ backside implant)
SiGe epilayer P+ Frontside contact
Backside contact
Si substrate N+
Si epilayer N–
14
Epilayer(s)
Wafer ID Si substrate thickness(es) andcomposition
dopant(s) doping concentrations(s)(cm–3)
First series (6 types)
50584G-J 22.1 nm, 19.5% Ge n-type, phosphorus 1.8e19
50583G-J 21.8 nm, 20.5% Ge p-type, boron 1.6e19
50582F-J
n-type, 10-50 ? -cm
1e14 cm–3
21.2 nm, 20.1% Ge undoped undoped
50584A-F 22.1 nm, 19.5% Ge n-type, phosphorus 1.8e19
50583A-F 21.8 nm, 20.5% Ge p-type, boron 1.6e19
50582A-E
p-type, 10-50 ? -cm
8e14 cm–3
21.2 nm, 20.1% Ge undoped undoped
Second series (4 types)
1A70305
n-type, 1e19 cm-3 20.3 μm Si30 nm, 31% Ge
n-type, phosphorusp-type, boron
7e146.5e18
1B70307
p-type, 1e19 cm-3 20.3 μm Si30 nm, 31% Ge
p-type, boronn-type, phosphorus
5.2e141.1e19
2A70295/7
n-type, 1e19 cm-3 20.3 μm Si206 nm, 8% Ge
n-type, phosphorusp-type, boron
6e141.5e19
(3A*)70298 n-type, 1e19 cm-3
20.3 μm Si300? nm, 5.3% Ge
500? nm
n-type, phosphorusp-type, boronp-type, boron
6e143e17
1.3e19
Third series (4 types)
21** Si, n+ > 3e19* 20 μm Si n-type uniform doping, 2e14 to 6e14
22** Si, n+ > 3e19* 20 μm Si n-typegraded dopant concentration,
~1e15 at substrate to ~2e14 atSiGe epi layer
23** Si, n+ > 3e19*
20 μm SiGe, gradedGe fraction: 0% Ge atsubstrate to 20% atSiGe p+ epi layer
n-type uniform doping, 2e14 to 6e14
24*** Si, n+ > 3e19* Si, 20 μm n-typeuniform doping: 2e14 to 6e14Si,
thickness same as above(~100 nm), p+ 1e19
*This wafer was specified for another type of device, but was also used for diodes.
**Epi layer 2: SiGe, 20%Ge, maximize thickness (~100 nm), p+ 1e19.
***Epi layer 2: Si, thickness same as above (~100 nm), p+ 1e19.
15
SiGe vs Si Diode Characteristics
16
SiGe vs Si Forward Voltage
17
SiGe vs Si and SiC Forward Voltage
0
200
400
600
800
1000
1200
1400
-200 -150 -100 -50 0 50
Temperature (degrees C)
Fo
rwa
rd D
rop
(m
V)
SiCSiGeSi #1Si #2Si #3
Univ. of Auburn measurements.
SiGe
18
SiGe vs Si Reverse Recovery
Univ. of Auburn measurements.
19
SiGe vs Si Reverse Recovery
Univ. of Auburn measurements.
20
SiGe vs Si Reverse Recovery
MTECH Labs. measurements.
21
SiGe vs Si Reverse Recovery
MTECH Labs. measurements.
22
Outline
Authors and Sponsors
Goals and Applications
Why SiGe?
Designs and results
SiGe heterojunction diodes
Cryogenic power converter
Summary
23
SiGe Boost Converter
Outputcapacitor
SiGe diode
Switching pulse
Inductor
LoadSiGe HBT
+
–
Inputcapacitor
24 V in 48 V out
~20 – 300 K
Optoisolator
Drivecircuit
Pulsegenerator
Power supply
+
–
24
SiGe 100 W Cryo Boost Converter100 kHz, 24 V in, 48 V out
25
SiGe 100 W Cryo Boost ConverterBackside
26
Cryostat for Measuring 100 W Circuits
27
100 W SiGe Power Converter in Cryostat
28
SiGe vs Si diodes in 100 W Cryo Boost Converter
29
Outline
Authors and Sponsors
Goals and Applications
Why SiGe?
Designs and results
SiGe heterojunction diodes
Cryogenic power converter
Summary
30
Summary• Cryogenic power conversion is of interest for a range of
applications within DoD and elsewhere.
• For cryogenic power conversion, SiGe devices are potentially superior to devices based on Si or Ge.
• We are developing SiGe semiconductor devices for cryogenic power applications.
• We have simulated SiGe diodes: results indicate improvements over Si diodes and have guided design.
• We have designed, fabricated, and used SiGe diodes (and HBTs) in power converters operating at cryogenic temperatures and converting >100 W.
31
Outline
Authors and Sponsors
Goals and Applications
Why SiGe?
Designs and results
SiGe heterojunction diodes
Cryogenic power converter
Summary