Faculty of Mathematics and Computer Science
Formation and Annihilation of Hydrogen-Related
Donor States in Proton-Implanted and Subsequently
Plasma-Hydrogenated N-Type Float-Zone Silicon
Reinhart Job, University of Hagen, Germany
Franz-Josef Niedernostheide, Infineon Technologies AG, Germany
Hans-Joachim Schulze, Infineon Technologies AG, Germany
Holger Schulze, Infineon Technologies Austria AG, Austria
High-Purity-Silicon X, PRIME 2008, Joint International Meeting
• 214th Meeting of the ECS – The Electrochemical Society
• 2008 Fall Meeting of The Electrochemical Society of Japan
Honolulu, HI, USA, Oct. 12th – 17th, 2008
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
Faculty of Mathematics and Computer Science
Outline of the talk
•
Introduction
•
Experimental details
•
Results and discussion
•
Summary
Folie 2
Oct. 14th, 2008
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
Faculty of Mathematics and Computer Science
Outline of the talk
• Introduction
•
Experimental details
•
Results and discussion
•
Summary
Folie 3
Oct. 14th, 2008
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
Faculty of Mathematics and Computer Science
Introduction
•
Light ion implantation (H+, He+):
→ useful tool in semiconductor technology
→ can modify semiconductor properties
→ can influence a wide spatial range within the semiconductor
•
Applications of light ion implantation:
→ H+-, He+-implantation: charge carrier lifetime control
→ H+-implantation:
formation of hydrogen related donors after
post-implantation annealing procedures
⇒ Attractive for high-power device technology:
→ formation of deep n-type doped layers
→ penetration depth at a given energy higher than for standard donors (P)
→ proton induced doping requires moderate thermal annealing regimes
Folie 4
Oct. 14th, 2008
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
Faculty of Mathematics and Computer Science
Introduction
⇒ In this presentation:
→ investigation of two-step processes in FZ Si wafers
→ successive H+-implantation and H-plasma treatments
(temperatures during H-plasma exposures: up to 500 °C)
→ formation and annihilation of n-type doping profiles
Folie 5
Oct. 14th, 2008
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
Faculty of Mathematics and Computer Science
Outline of the talk
•
Introduction
• Experimental details
•
Results and discussion
•
Summary
Folie 6
Oct. 14th, 2008
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
Faculty of Mathematics and Computer Science
Experimental details
•
•
•
•
Substrates:
- n-type float zone (FZ) silicon wafer, (100)-oriented
- ρ = 30 Ωcm, phosphorous doped
H+-implantation: - “shallow” implantation: E = 1 MeV, Rp ≈ 16.5 µm*
D = 1×1014 cm-2
- “deep” implantation:
E = 3 MeV, Rp ≈ 92.8 µm*
D = 1×1014 cm-2
H-plasma:
- RF generator:
ν = 13.56 MHz
- plasma power:
PPl = 150 W
- H2-flux:
FH2 = 50 sccm
- Ar-flux*:
FAr = 50 sccm
- chamber pressure:
p = 7.4×10-3 mbar
- process temperatures: TS = 350, 400, 450, 500 °C
Analyses:
- two-point-probe spreading resistance measurements
* projected ion ranges Rp (SRIM 2008 simulations with full damage cascades)
Folie 7
Oct. 14th, 2008
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
Faculty of Mathematics and Computer Science
Outline of the talk
•
Introduction
•
Experimental details
• Results and discussion
•
Folie 8
Summary
Oct. 14th, 2008
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
Faculty of Mathematics and Computer Science
+
H -Implantation & 15 min H-Plasma
500 °C
Spreading resistance analyses
•
H+-implantation:
E = 1 MeV
D = 1×1014 cm-2
H-plasma treatment at various
substrate temperatures:
- 350 °C
- 400 °C
t = 15 min
- 450 °C
- 500 °C
Spreading Resistance (Ohm)
•
5
10
450 °C
5
10
400 °C
5
10
350 °C
5
10
0
5
10
15
20
25
Depth (µm)
Folie 9
Oct. 14th, 2008
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
Faculty of Mathematics and Computer Science
+
H -Implantation & 15 min H-Plasma
500 °C
15
10
Spreading resistance analyses
+
H -Implantation & 15 min H-Plasma
500 °C
5
Spreading Resistance (Ohm)
10
450 °C
5
10
400 °C
5
14
10
-3
Transformation of SR profiles into
doping concentration profiles
Carrier Concentration (cm )
•
450 °C
15
10
14
10
400 °C
15
10
14
10
350 °C
15
10
10
350 °C
14
5
10
10
0
5
10
15
Depth (µm)
Folie 10
Oct. 14th, 2008
20
25
0
5
10
15
20
25
Depth (µm)
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
Faculty of Mathematics and Computer Science
+
H -Implantation & 15 min H-Plasma
500 °C
15
10
Spreading resistance analyses
•
•
14
10
-3
Region deeper than Rp:
initial n-type doping concentration
of untreated FZ Si material
Region close to Rp:
→ surplus n-type doping
→ n-type doping concentration
enhanced by one order of
magnitude
Region towards Rp (up to 15 µm
depth):
→ surplus n-type doping profile
follows implantation damage
profile
→ vacancy concentration profile
Carrier Concentration (cm )
•
450 °C
15
10
14
10
400 °C
15
10
14
10
350 °C
15
10
14
10
0
5
10
15
20
25
Depth (µm)
Folie 11
Oct. 14th, 2008
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
Faculty of Mathematics and Computer Science
+
H -Implantation & 15 min H-Plasma
500 °C
15
10
Spreading resistance analyses
•
•
14
10
-3
Region deeper than Rp:
initial n-type doping concentration
of untreated FZ Si material
Region close to Rp:
→ surplus n-type doping
→ n-type doping concentration
enhanced by one order of
magnitude
Region towards Rp (up to 15 µm
depth):
→ surplus n-type doping profile
follows implantation damage
profile
→ vacancy concentration profile
Carrier Concentration (cm )
•
450 °C
15
10
14
10
400 °C
15
10
14
10
350 °C
15
10
14
10
0
5
10
15
20
25
Depth (µm)
Folie 12
Oct. 14th, 2008
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
Faculty of Mathematics and Computer Science
+
H -Implantation & 15 min H-Plasma
500 °C
15
10
Spreading resistance analyses
•
•
14
10
-3
Region deeper than Rp:
initial n-type doping concentration
of untreated FZ Si material
Region close to Rp:
→ surplus n-type doping
→ n-type doping concentration
enhanced by one order of
magnitude
Region towards Rp (up to 15 µm
depth):
→ surplus n-type doping profile
follows implantation damage
profile
→ vacancy concentration profile
Carrier Concentration (cm )
•
450 °C
15
10
14
10
400 °C
15
10
14
10
350 °C
15
10
14
10
0
5
10
15
20
25
Depth (µm)
Folie 13
Oct. 14th, 2008
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
Faculty of Mathematics and Computer Science
+
H -Implantation & 15 min H-Plasma
500 °C
15
10
Spreading resistance analyses
14
10
-3
Region close to the surface:
→ n-type doping is a bit enhanced
(factor of 2) for H-plasma treatment at 350 °C and 400 °C
Region towards the surface:
→ n-type doping towards the surface
more stronger enhanced at
450 °C and 500 °C
Region close to the surface:
→ doping concentration reduced
(H-plasma at 450 °C)
→ doping concentration below
initial doping n-type level
(H-plasma at 500 °C)
Carrier Concentration (cm )
•
•
•
450 °C
15
10
14
10
400 °C
15
10
14
10
350 °C
15
10
14
10
0
5
10
15
20
25
Depth (µm)
Folie 14
Oct. 14th, 2008
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
Faculty of Mathematics and Computer Science
+
H -Implantation & 15 min H-Plasma
500 °C
15
10
Spreading resistance analyses
14
10
-3
Region close to the surface:
→ n-type doping is a bit enhanced
(factor of 2) for H-plasma treatment at 350 °C and 400 °C
Region towards the surface:
→ n-type doping towards the surface
more stronger enhanced at
450 °C and 500 °C
Region close to the surface:
→ doping concentration reduced
(H-plasma at 450 °C)
→ doping concentration below
initial doping n-type level
(H-plasma at 500 °C)
Carrier Concentration (cm )
•
•
•
450 °C
15
10
14
10
400 °C
15
10
14
10
350 °C
15
10
14
10
0
5
10
15
20
25
Depth (µm)
Folie 15
Oct. 14th, 2008
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
Faculty of Mathematics and Computer Science
+
H -Implantation & 15 min H-Plasma
500 °C
15
10
Spreading resistance analyses
14
10
-3
Region close to the surface:
→ n-type doping is a bit enhanced
(factor of 2) for H-plasma treatment at 350 °C and 400 °C
Region towards the surface:
→ n-type doping towards the surface
more stronger enhanced at
450 °C and 500 °C
Region close to the surface:
→ doping concentration reduced
(H-plasma at 450 °C)
→ doping concentration below
initial doping n-type level
(H-plasma at 500 °C)
Carrier Concentration (cm )
•
•
•
450 °C
15
10
14
10
400 °C
15
10
14
10
350 °C
15
10
14
10
0
5
10
15
20
25
Depth (µm)
Folie 16
Oct. 14th, 2008
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
Faculty of Mathematics and Computer Science
+
H -Implantation & 15 min H-Plasma
500 °C
15
10
Spreading resistance analyses
14
10
-3
Conclusions (I):
→ Region near Rp:
) hydrogen-related shallow
donor formation occurs
) vacancies play a significant role
⇒ excessive donor concentration
⇓
vacancy-hydrogen-complexes
Carrier Concentration (cm )
•
450 °C
15
10
14
10
400 °C
15
10
14
10
350 °C
15
10
14
10
0
5
10
15
20
Depth (µm)
Folie 17
Oct. 14th, 2008
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
25
Faculty of Mathematics and Computer Science
+
H -Implantation & 15 min H-Plasma
500 °C
15
10
Spreading resistance analyses
14
10
-3
Conclusions (II):
→ Region towards the surface:
) vacancies diffuse towards the
surface during plasma exposure
at elevated temperatures
⇒ enhanced vacancy concentration
toward the surface
⇓
vacancy-hydrogen-complexes
⇓
excessive donor concentration
Carrier Concentration (cm )
•
450 °C
15
10
14
10
400 °C
15
10
14
10
350 °C
15
10
14
10
0
5
10
15
20
Depth (µm)
Folie 18
Oct. 14th, 2008
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
25
Faculty of Mathematics and Computer Science
+
H -Implantation & 15 min H-Plasma
500 °C
15
10
Spreading resistance analyses
14
10
-3
Conclusions (III):
→ Region close to the surface (I):
) formation of acceptor-like
defect complexes
) acceptor-like defect complexes
are passivated by hydrogen at
lower temperatures
) at higher temperatures acceptorlike defect complexes become
electrically active again
⇒ compensation of n-type doping
Carrier Concentration (cm )
•
450 °C
15
10
14
10
400 °C
15
10
14
10
350 °C
15
10
14
10
0
5
10
15
20
Depth (µm)
Folie 19
Oct. 14th, 2008
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
25
Faculty of Mathematics and Computer Science
+
H -Implantation & 60 min H-Plasma
500 °C
Spreading resistance analyses
•
13
10
450 °C
-3
H+-implantation:
E = 1 MeV
D = 1×1014 cm-2
H-plasma treatment at various
substrate temperatures:
- 350 °C
- 400 °C
t = 60 min
- 450 °C
- 500 °C
Carrier Concentration (cm )
•
14
10
14
10
13
10
400 °C
14
10
13
10
350 °C
14
10
13
10
0
5
10
15
20
25
Depth (µm)
Folie 20
Oct. 14th, 2008
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
Faculty of Mathematics and Computer Science
+
H -Implantation & 60 min H-Plasma
500 °C
Spreading resistance analyses
•
However, close to the surface
n-type doping compensated for
by acceptor-like defects
13
10
450 °C
-3
Donor states in the subsurface
region down to Rp disappeared
) initial homogeneous doping
concentration is re-established
Carrier Concentration (cm )
•
14
10
14
10
13
10
400 °C
14
10
13
10
350 °C
14
10
13
10
0
5
10
15
20
25
Depth (µm)
Folie 21
Oct. 14th, 2008
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
Faculty of Mathematics and Computer Science
+
H -Implantation & 60 min H-Plasma
500 °C
Spreading resistance analyses
•
However, close to the surface
n-type doping compensated for
by acceptor-like defects
13
10
450 °C
-3
Donor states in the subsurface
region down to Rp disappeared
) initial homogeneous doping
concentration is re-established
Carrier Concentration (cm )
•
14
10
14
10
13
10
400 °C
14
10
13
10
350 °C
14
10
13
10
0
5
10
15
20
25
Depth (µm)
Folie 22
Oct. 14th, 2008
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
Faculty of Mathematics and Computer Science
Spreading resistance analyses
•
•
60 min H-Plasma (400 °C) (no implantation)
15
10
-3
Doping Concentration (cm )
No H+-implantation
Only 60 min H-plasma
treatment at 400 °C
substrate temperature
) No formation of doping
profiles!
• Similar results for H-plasma
exposure at other substrate
temperatures up to 500 °C
14
10
13
10
0
5
10
15
20
25
Depth (µm)
Folie 23
Oct. 14th, 2008
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
Faculty of Mathematics and Computer Science
Spreading resistance analyses
•
•
15
10
60 min H-Plasma (400 °C) (no implantation)
-3
Doping Concentration (cm )
No H+-implantation
Only 60 min H-plasma
treatment at 400 °C
substrate temperature
) No formation of doping
profiles!
• Similar results for H-plasma
exposure at other substrate
temperatures up to 500 °C
14
10
13
10
⇒ Acceptor-like defects can
0
not be attributed to plasma
damage alone!
⇒ vacancies must be involved !!!
Folie 24
Oct. 14th, 2008
5
10
15
20
25
Depth (µm)
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
Faculty of Mathematics and Computer Science
+
H -Implantation & 60 min H-Plasma
500 °C
Spreading resistance analyses
13
10
450 °C
-3
Conclusion:
→ strong injection of hydrogen
during long-term plasma
treatment
→ transformation of vacancyand hydrogen-related donor
states into electrically
inactive defects, e. g. V-H4
→ acceptor-like defects near the
surface
) hydrogenated vacancy or
multi-vacancy complexes,
e. g. V2-H2 (?)
Carrier Concentration (cm )
•
14
10
14
10
13
10
400 °C
14
10
13
10
350 °C
14
10
13
10
0
5
10
15
20
25
Depth (µm)
Folie 25
Oct. 14th, 2008
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
Faculty of Mathematics and Computer Science
+
3 MeV H -Implantation & H-Plasma (400 °C)
16
15 min H-Plasma
10
Spreading resistance analyses
•
14
10
-3
Deep H+-implantation:
E = 3 MeV
D = 1×1014 cm-2
H-plasma treatment at 400 °C
substrate temperature for
various duration:
- t = 15 min (above)
- t = 60 min (below)
Carrier Concentration (cm )
•
15
10
13
10
12
10
16
10
60 min H-Plasma
15
10
14
10
13
10
12
10
0
20
40
60
80
100
Depth (µm)
Folie 26
Oct. 14th, 2008
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
Faculty of Mathematics and Computer Science
+
3 MeV H -Implantation & H-Plasma (400 °C)
16
15 min H-Plasma
10
Spreading resistance analyses
•
14
10
-3
Region close to Rp:
→ surplus n-type doping caused by
vacancy-hydrogen-complexes
(15 min H-plasma exposure)
Region at 30 µm – 85 µm depth:
→ strong reduction of n-type
carrier concentration
) implantation damage
(15 min H-plasma exposure)
Carrier Concentration (cm )
•
15
10
13
10
12
10
16
10
60 min H-Plasma
15
10
14
10
13
10
12
10
0
20
40
60
80
100
Depth (µm)
Folie 27
Oct. 14th, 2008
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
Faculty of Mathematics and Computer Science
+
3 MeV H -Implantation & H-Plasma (400 °C)
16
15 min H-Plasma
10
Spreading resistance analyses
•
14
10
-3
Region close to Rp:
→ surplus n-type doping caused by
vacancy-hydrogen-complexes
(15 min H-plasma exposure)
Region at 30 µm – 85 µm depth:
→ strong reduction of n-type
carrier concentration
) implantation damage
(15 min H-plasma exposure)
Carrier Concentration (cm )
•
15
10
13
10
12
10
16
10
60 min H-Plasma
15
10
14
10
13
10
12
10
0
20
40
60
80
100
Depth (µm)
Folie 28
Oct. 14th, 2008
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
Faculty of Mathematics and Computer Science
+
3 MeV H -Implantation & H-Plasma (400 °C)
16
15 min H-Plasma
10
Spreading resistance analyses
Folie 29
Oct. 14th, 2008
14
10
-3
Region down to ∼30 µm depth:
→ indiffusing hydrogen passivates
implantation damage
) toward the surface:
initial doping level recovered
(15 min H-plasma exposure)
→ surplus n-type doping profile
follows the vacancy concentration profile
) vacancy-hydrogen-defects
(15 min H-plasma exposure)
→ at the surface weak reduction
of the n-type doping
) acceptor-like defect states
(15 min H-plasma exposure)
Carrier Concentration (cm )
•
15
10
13
10
12
10
16
10
60 min H-Plasma
15
10
14
10
13
10
12
10
0
20
40
60
80
100
Depth (µm)
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
Faculty of Mathematics and Computer Science
+
3 MeV H -Implantation & H-Plasma (400 °C)
16
15 min H-Plasma
10
Spreading resistance analyses
Folie 30
Oct. 14th, 2008
14
10
-3
Region down to ∼30 µm depth:
→ indiffusing hydrogen passivates
implantation damage
) toward the surface:
initial doping level recovered
(15 min H-plasma exposure)
→ surplus n-type doping profile
follows the vacancy concentration profile
) vacancy-hydrogen-defects
(15 min H-plasma exposure)
→ at the surface weak reduction
of the n-type doping
) acceptor-like defect states
(15 min H-plasma exposure)
Carrier Concentration (cm )
•
15
10
13
10
12
10
16
10
60 min H-Plasma
15
10
14
10
13
10
12
10
0
20
40
60
80
100
Depth (µm)
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
Faculty of Mathematics and Computer Science
+
3 MeV H -Implantation & H-Plasma (400 °C)
16
15 min H-Plasma
10
Spreading resistance analyses
Folie 31
Oct. 14th, 2008
14
10
-3
Region down to ∼30 µm depth:
→ indiffusing hydrogen passivates
implantation damage
) toward the surface:
initial doping level recovered
(15 min H-plasma exposure)
→ surplus n-type doping profile
follows the vacancy concentration profile
) vacancy-hydrogen-defects
(15 min H-plasma exposure)
→ at the surface weak reduction
of the n-type doping
) acceptor-like defect states
(15 min H-plasma exposure)
Carrier Concentration (cm )
•
15
10
13
10
12
10
16
10
60 min H-Plasma
15
10
14
10
13
10
12
10
0
20
40
60
80
100
Depth (µm)
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
Faculty of Mathematics and Computer Science
+
3 MeV H -Implantation & H-Plasma (400 °C)
16
15 min H-Plasma
10
Spreading resistance analyses
•
•
Folie 32
Oct. 14th, 2008
14
10
-3
Region close to Rp:
→ surplus n-type doping caused by
vacancy-hydrogen-complexes
(60 min H-plasma exposure)
Subsurface region down to Rp:
→ indiffusing hydrogen passivates
implantation damage (V-H4)
) initial n-type doping level
(60 min H-plasma exposure)
→ surplus n-type doping follows
vacancy concentration profile
Close to the surface:
→ acceptor-like defect states
compensate for n-type doping
(60 min H-plasma exposure)
Carrier Concentration (cm )
•
15
10
13
10
12
10
16
10
60 min H-Plasma
15
10
14
10
13
10
12
10
0
20
40
60
80
100
Depth (µm)
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
Faculty of Mathematics and Computer Science
+
3 MeV H -Implantation & H-Plasma (400 °C)
16
15 min H-Plasma
10
Spreading resistance analyses
•
Folie 33
Oct. 14th, 2008
14
10
-3
Region close to Rp:
→ surplus n-type doping caused by
vacancy-hydrogen-complexes
(60 min H-plasma exposure)
Subsurface region down to Rp:
→ indiffusing hydrogen passivates
implantation damage (V-H4)
) initial n-type doping level
→ surplus n-type doping follows
vacancy concentration profile
(60 min H-plasma exposure)
• Close to the surface:
→ acceptor-like defect states
compensate for n-type doping
(60 min H-plasma exposure)
Carrier Concentration (cm )
•
15
10
13
10
12
10
16
10
60 min H-Plasma
15
10
14
10
13
10
12
10
0
20
40
60
80
100
Depth (µm)
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
Faculty of Mathematics and Computer Science
+
3 MeV H -Implantation & H-Plasma (400 °C)
16
15 min H-Plasma
10
Spreading resistance analyses
•
•
Folie 34
Oct. 14th, 2008
14
10
-3
Region close to Rp:
→ surplus n-type doping caused by
vacancy-hydrogen-complexes
(60 min H-plasma exposure)
Subsurface region down to Rp:
→ indiffusing hydrogen passivates
implantation damage (V-H4)
) initial n-type doping level
(60 min H-plasma exposure)
→ surplus n-type doping follows
vacancy concentration profile
Close to the surface:
→ acceptor-like defect states
compensate for n-type doping
(60 min H-plasma exposure)
Carrier Concentration (cm )
•
15
10
13
10
12
10
16
10
60 min H-Plasma
15
10
14
10
13
10
12
10
0
20
40
60
80
100
Depth (µm)
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
Faculty of Mathematics and Computer Science
Outline of the talk
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Introduction
→ Light ion implantation into silicon
→ Plasma hydrogenation of silicon
→ Hydrogen related donor states in silicon
Experimental details
→ Sample preparation
→ Experimental analyses
Results and discussion
→ Formation of doping profiles by H+-implantation and subsequent
plasma hydrogenation at elevated temperatures
→ Mechanisms of donor states formation
Summary
Oct. 14th, 2008
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
Faculty of Mathematics and Computer Science
Summary
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Influence of plasma hydrogenation on H+-implanted FZ Si was studied
Analysis as done be means of spreading resistance measurements
It was observed that
) surplus n-type doping occurs near Rp (one order of magnitude above
the initial doping level)
) surplus n-type doping occurs also towards the wafer surface
for 15 min H-plasma exposure (less strong)
→ surface acts as a getter center for vacancies
) hydrogenated vacancy defect complexes are responsible for surplus
n-type doping in the subsurface layer down to Rp
) near the surface (down to a depth of ∼2 µm) acceptor-like states were
created, which compensate for the n-type doping
) acceptor-like defect states can be attributed to (multi-) vacancyhydrogen complexes
Oct. 14th, 2008
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors
Faculty of Mathematics and Computer Science
Acknowledgements
The technical support of
Mrs. Renate Bommersbach
(Infineon Technologies AG, Munich)
&
Mr. Josef Niedermeyr
(Infineon Technologies AG, Munich)
is gratefully acknowledged.
Folie 37
Oct. 14th, 2008
Prof. Dr. rer. nat. Reinhart Job, Power Devices & Sensors