Transcript Development of Ge and Si-Ge Semiconductor Devices for

Novel SiGe Semiconductor
Devices for
Cryogenic Power Electronics
ICMC/CEC August-September 2005
Keystone, Colorado
Outline
Authors and Sponsors
Goals and Applications
Why SiGe?
Designs and results
SiGe heterojunction diodes
Cryogenic power converter
Summary
2
Outline
Authors and Sponsors
Goals and Applications
Why SiGe?
Designs and results
SiGe heterojunction diodes
Cryogenic power converter
Summary
3
Authors
Rufus Ward, Bill Dawson, Lijun Zhu, Randall Kirschman
GPD Optoelectronics Corp., Salem, New Hampshire
GPD Optoelectronics
Corporation
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
4
Sponsors
US Office of Naval Research
US Army Aviation and Missiles Command
Defense Advanced Research Projects Agency
5
Outline
Authors and Sponsors
Goals and Applications
Why SiGe?
Designs and results
SiGe heterojunction diodes
Cryogenic power converter
Summary
6
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
7
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)
8
Outline
Authors and Sponsors
Goals and Applications
Why SiGe?
Designs and results
SiGe heterojunction diodes
Cryogenic power converter
Summary
9
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
10
Outline
Authors and Sponsors
Goals and Applications
Why SiGe?
Designs and results
SiGe heterojunction diodes
Cryogenic power converter
Summary
11
SiGe Diode Simulations
12
SiGe Heterostructure Diode
Frontside contact
SiGe epilayer P+
Si epilayer N–
Si substrate N+
(N+ backside implant)
Backside contact
13
Epilayer(s)
Wafer ID
Si substrate
thickness(es) and
composition
dopant(s)
doping concentrations(s)
–3
(cm )
First series (6 types)
50584G-J
50583G-J
n-type, 10-50 ? -cm
–3
22.1 nm, 19.5% Ge
n-type, phosphorus
1.8e19
21.8 nm, 20.5% Ge
p-type, boron
1.6e19
21.2 nm, 20.1% Ge
undoped
undoped
22.1 nm, 19.5% Ge
n-type, phosphorus
1.8e19
21.8 nm, 20.5% Ge
p-type, boron
1.6e19
21.2 nm, 20.1% Ge
undoped
undoped
1e14 cm
50582F-J
50584A-F
50583A-F
50582A-E
p-type, 10-50 ? -cm
–3
8e14 cm
Second series (4 types)
1A
70305
n-type, 1e19 cm
-3
20.3 μm Si
30 nm, 31% Ge
n-type, phosphorus
p-type, boron
7e14
6.5e18
1B
70307
p-type, 1e19 cm
-3
20.3 μm Si
30 nm, 31% Ge
p-type, boron
n-type, phosphorus
5.2e14
1.1e19
2A
70295/7
n-type, 1e19 cm
-3
20.3 μm Si
206 nm, 8% Ge
n-type, phosphorus
p-type, boron
6e14
1.5e19
(3A*)
70298
n-type, 1e19 cm
-3
20.3 μm Si
300? nm, 5.3% Ge
500? nm
n-type, phosphorus
p-type, boron
p-type, boron
6e14
3e17
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-type
graded dopant concentration,
~1e15 at substrate to ~2e14 at
SiGe epi layer
23**
Si, n+ > 3e19*
20 μm SiGe, graded
Ge fraction: 0% Ge at
substrate to 20% at
SiGe p+ epi layer
n-type
uniform doping, 2e14 to 6e14
24***
Si, n+ > 3e19*
Si, 20 μm
n-type
uniform 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.
14
SiGe vs Si Diode Characteristics
15
SiGe vs Si Forward Voltage
16
SiGe vs Si and SiC Forward Voltage
1400
Forward Drop (mV)
1200
1000
SiC
SiGe
Si #1
Si #2
Si #3
800
600
SiGe
400
200
0
-200
-150
-100
-50
0
50
Temperature (degrees C)
Univ. of Auburn measurements.
17
SiGe vs Si Reverse Recovery
Univ. of Auburn measurements.
18
SiGe vs Si Reverse Recovery
Univ. of Auburn measurements.
19
SiGe vs Si Reverse Recovery
MTECH Labs. measurements.
20
SiGe vs Si Reverse Recovery
MTECH Labs. measurements.
21
Outline
Authors and Sponsors
Goals and Applications
Why SiGe?
Designs and results
SiGe heterojunction diodes
Cryogenic power converter
Summary
22
SiGe Boost Converter
48 V out
24 V in
Inductor
SiGe diode
Input
capacitor
+
Power
supply
Output
capacitor
SiGe HBT
Load
–
Pulse
generator
+
–
Opto
isolator
Drive
circuit
~20 – 300 K
Switching pulse
23
SiGe 100 W Cryo Boost Converter
100 kHz, 24 V in, 48 V out
24
SiGe 100 W Cryo Boost Converter
Backside
25
Cryostat for Measuring 100 W Circuits
26
100 W SiGe Power Converter in Cryostat
27
SiGe vs Si diodes
in 100 W Cryo Boost Converter
28
Outline
Authors and Sponsors
Goals and Applications
Why SiGe?
Designs and results
SiGe heterojunction diodes
Cryogenic power converter
Summary
29
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.
30
Outline
Authors and Sponsors
Goals and Applications
Why SiGe?
Designs and results
SiGe heterojunction diodes
Cryogenic power converter
Summary
31