h. wolf 1 , f. wagner 1 , j. kronenberg 1 , h. wolf 1 , th. wichert 1 , k. johnston 1
DESCRIPTION
Diffusion behaviour of short lived isotopes in II‑VI semiconductors. H. Wolf 1 , F. Wagner 1 , J. Kronenberg 1 , H. Wolf 1 , Th. Wichert 1 , K. Johnston 1 and the ISOLDE Collaboration. 1) Technische Physik, Universität des Saarlandes, D-66123 Saarbrücken, Germany. - PowerPoint PPT PresentationTRANSCRIPT
1
H. Wolf1, F. Wagner1, J. Kronenberg1, H. Wolf1, Th. Wichert1, K. Johnston1
and the ISOLDE Collaboration
1) Technische Physik, Universität des Saarlandes, D-66123 Saarbrücken, Germany
Supported by the BMBF, contract 05 KK7TS1
Diffusion behaviour of short lived isotopesin II‑VI semiconductors
2
Workshop 2006
Ag in CdTe: 828K, 60 min
0 200 400 600 800
1011
1012
1013
0 200 4001012
1013
1014
1015
0 200 400 600 800
1012
1013
1014
Cd atmosphere Te atmospherevacuum
conc
entra
tion
(cm
-3)
depth (m)
depth (m)
depth (m)
• Up hill diffusion• Not explainable by fick´s laws
0 100 200 300 400 500108
109
1010
1011
1012
1013
1014
conc
entra
tion
(cm
-3)
depth (µm)
Ag in CdTe: 550K, 30 min
vacuum Cd atmosphere
tAg
AgDAgJ
)(
H. Wolf, F. Wagner, Th. Wichert, Phys. Rev. Lett. 94, 125901 (2005)
3
0.5 – 0.8 mm 500 K - 1000 K
annealing111Ag
30 nm
111Ag
111Ag
radiotracer technique
CdTe
4
radiotracer technique
0 100 200 300 400 500108
109
1010
1011
1012
1013
1014
conc
entra
tion
(cm
-3)
depth (µm)
5
Workshop 2006
Ag in CdTe: 828K, 60 min
0 200 400 600 800
1011
1012
1013
0 200 4001012
1013
1014
1015
0 200 400 600 800
1012
1013
1014
Cd atmosphere Te atmospherevacuum
conc
entra
tion
(cm
-3)
depth (m)
depth (m)
depth (m)
Up hill diffusionWhat can we learn?
6
Workshop 2007
• Interstitial Cd
• Donator (Cdi++)
•Cd vacancy
• Acceptor (VCd--)
• Substitutionell Ag
• Acceptor (AgCd-)
• Interstitial Ag
• Donator (Agi+)
Cd Te
7
-0,2
-0,1
0,0
0,1
0 200 400 600 800
1011
1012
1013
-4x1016
-3x1016
-2x1016
-1x1016
01x1016
2x1016
VCd
--Cdi++
depth (µm)
µ F eV
n npCd
i++
Ag+i
conc
entra
tion
(cm
-3)
[C
] (cm
-3)
0 200 400 600 800
1011
1012
1013
-4x1016
-3x1016
-2x1016
-1x1016
01x1016
2x1016
Ag+i
conc
entra
tion
(cm
-3)
depth (µm)
[C
] (cm
-3)
Cd-atmosphere (828 K 60 min)
• Cd-atmosphere: Cdi in diffusion
[ΔC] = [Cdi]-[VCd]
• [ΔC] determines µF
• [Ag] = [Agi+]
• Agi+ behaves like h+
• Ag profile reflect µF und [ΔC]
Workshop 2007
[ΔCini]
Cdi Cdi
8
Workshop 2007
Ag in CdTe: 828K, 60 min
0 200 400 600 800
1011
1012
1013
0 200 4001012
1013
1014
1015
0 200 400 600 800
1012
1013
1014
Cd atmosphere Te atmospherevacuum
conc
entra
tion
(cm
-3)
depth (m)
depth (m)
depth (m)
Information about: Diffusion coefficients Formation energies Ionizations energies
9
Ag
Ia
IIa
IIIb IV b Vb V Ib V IIb V III Ib IIb
IIIa IVa Va V Ia V IIa
V III
Zn
Cd In
N
Sb
S
Se
Te
Cl
Br
I
As33
15
7
H
B e
M g
C a S c T i
S r Y
V C r M n
Z r N b M o T c
F e C o N i
R u R h P d
B
A l
G a
C
S i
G e
S n
P
O F
H e
N e
A r
K r
X e
C u
4
12
20 21 22 23 24 25 26 27 28 29 30 31
13
5
32
14
6
34
16
8
35
17
9
36
18
10
2
38 39 40 41 42 43 44 45 46 47 48 49 50 51 53 54
Li
Rb
Na
K
1
3
11
19
37
Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu58 59 60 61 62 63 64 65 66 67 68 69 70 71
La57
Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi56 57 72 73 74 75 76 77 78 79 80 81 82 83
Cs55
II-VI semiconductors
10
Ag in different semiconductors
0 200 400 600 800109
1010
1011
1012
1013
conc
entra
tion
(cm
-3)
depth (µm)
0 200 400108
109
1010
1011
1012
1013
1014
conc
entra
tion
(cm
-3)
depth (µm)
0 200 400 600 800
1011
1012
1013
conc
entra
tion
(cm
-3)
depth (µm)
CdTe Cd0.96Zn0.04Te ZnTe828K, 60 min 828K, 60 min 928K, 24 h
Comparable behavior of Ag in different II-VI semiconductors
Cd atmosphere Cd atmosphere Zn atmosphere
11
Ag
Ia
IIa
IIIb IV b Vb V Ib V IIb V III Ib IIb
IIIa IVa Va V Ia V IIa
V III
Zn
Cd In
N
Sb
S
Se
Te
Cl
Br
I
As33
15
7
H
B e
M g
C a S c T i
S r Y
V C r M n
Z r N b M o T c
F e C o N i
R u R h P d
B
A l
G a
C
S i
G e
S n
P
O F
H e
N e
A r
K r
X e
C u
4
12
20 21 22 23 24 25 26 27 28 29 30 31
13
5
32
14
6
34
16
8
35
17
9
36
18
10
2
38 39 40 41 42 43 44 45 46 47 48 49 50 51 53 54
Li
Rb
Na
K
1
3
11
19
37
Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu58 59 60 61 62 63 64 65 66 67 68 69 70 71
La57
Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi56 57 72 73 74 75 76 77 78 79 80 81 82 83
Cs55
12
Comparison Ag and Cu in CdTe
0 200 400 600 8001010
1011
1012
1013
Kon
zent
ratio
n (c
m-3)
Tiefe (m)
CdTe102767Cu
0 200 400 600 800
1011
1012
1013
Kon
zent
ratio
n (c
m-3)
Tiefe (m)
Cu Ag
depth [µm]
conc
entra
tion
[cm
-3]
depth [µm]
Comparable behavior of Ag and Cu
Cd atmosphere, 828 K, 60 min
13
Ag
Ia
IIa
IIIb IV b Vb V Ib V IIb V III Ib IIb
IIIa IVa Va V Ia V IIa
V III
Zn
Cd In
N
Sb
S
Se
Te
Cl
Br
I
As33
15
7
H
B e
M g
C a S c T i
S r Y
V C r M n
Z r N b M o T c
F e C o N i
R u R h P d
B
A l
G a
C
S i
G e
S n
P
O F
H e
N e
A r
K r
X e
C u
4
12
20 21 22 23 24 25 26 27 28 29 30 31
13
5
32
14
6
34
16
8
35
17
9
36
18
10
2
38 39 40 41 42 43 44 45 46 47 48 49 50 51 53 54
Li
Rb
Na
K
1
3
11
19
37
Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu58 59 60 61 62 63 64 65 66 67 68 69 70 71
La57
Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi56 57 72 73 74 75 76 77 78 79 80 81 82 83
Cs55
14
Au diffusion in CdZnTe
D(Au) >> D(Teramoto et al.) 1µm
No uphil diffusion?
I. Teramoto and S. Takayanagi, J. Phys. Soc. Jpn. 17 (1962) 1137.
0 200 400 600 800109
1010
1011
1012
conc
entra
tion
(cm
-3)
depth (µm)
CdZnTe: 828K, 60 min, Cd atmosphere
Pre anneal: 928K, Te atmosphere
0 200 400 600 800109
1010
1011
1012
conc
entra
tion
(cm
-3)
depth (µm)
15
Au diffusion in CdZnTe
0 200 400 600 800
1011
1012
1013
-4x1016
-3x1016
-2x1016
-1x1016
01x1016
2x1016
Ag+i
conc
entra
tion
(cm
-3)
depth (µm)
[C
] (cm
-3)
[ΔCini]
Cdi Cdi
16
Au diffusion in CdZnTe
0 200 400 600 800109
1010
1011
1012
conc
entra
tion
(cm
-3)
depth (µm)
CdZnTe: 828K, 60 min, Cd atmosphere
Up hill diffusion can be observed for Au [ΔCini] < 0 (VCd
--)
Pre anneal: 928K, Te atmosphere
0 200 400 600 800109
1010
1011
1012
conc
entra
tion
(cm
-3)
depth (µm)
17
Ag
Ia
IIa
IIIb IV b Vb V Ib V IIb V III Ib IIb
IIIa IVa Va V Ia V IIa
V III
Zn
Cd In
N
Sb
S
Se
Te
Cl
Br
I
As33
15
7
H
B e
M g
C a S c T i
S r Y
V C r M n
Z r N b M o T c
F e C o N i
R u R h P d
B
A l
G a
C
S i
G e
S n
P
O F
H e
N e
A r
K r
X e
C u
4
12
20 21 22 23 24 25 26 27 28 29 30 31
13
5
32
14
6
34
16
8
35
17
9
36
18
10
2
38 39 40 41 42 43 44 45 46 47 48 49 50 51 53 54
Li
Rb
Na
K
1
3
11
19
37
Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu58 59 60 61 62 63 64 65 66 67 68 69 70 71
La57
Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi56 57 72 73 74 75 76 77 78 79 80 81 82 83
Cs55
18
Na diffusion in CdTe
Na diffusion show up hill diffusion
0 200 400 600 800108
109
1010
1011
10h: vacuum 1h: Cd atmosphere
conc
entra
tion
(cm
-3)
depth (µm)
Na: 750 K
19
0 200 400 600 800108
109
1010
1011
1012
1013
9h: vacuum10h: Cd atmosphere
conc
entra
tion
(cm
-3)
depth (µm)
n p
K diffusion in CdTe
Weak penetration of K diffusion in n-type part no peak-shaped profile
0 200 400 600 800
1011
1012
1013
0 200 4001012
1013
1014
1015
0 200 400 600 800
1012
1013
1014
Cd atmosphere Te atmospherevacuum
conc
entra
tion
(cm
-3)
depth (m)
depth (m)
depth (m)
n p
K: 750K Ag: 828K
20
Ag
Ia
IIa
IIIb IV b Vb V Ib V IIb V III Ib IIb
IIIa IVa Va V Ia V IIa
V III
Zn
Cd In
N
Sb
S
Se
Te
Cl
Br
I
As33
15
7
H
B e
M g
C a S c T i
S r Y
V C r M n
Z r N b M o T c
F e C o N i
R u R h P d
B
A l
G a
C
S i
G e
S n
P
O F
H e
N e
A r
K r
X e
C u
4
12
20 21 22 23 24 25 26 27 28 29 30 31
13
5
32
14
6
34
16
8
35
17
9
36
18
10
2
38 39 40 41 42 43 44 45 46 47 48 49 50 51 53 54
Li
Rb
Na
K
1
3
11
19
37
Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu58 59 60 61 62 63 64 65 66 67 68 69 70 71
La57
Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi56 57 72 73 74 75 76 77 78 79 80 81 82 83
Cs55
K, Mn and Fe diffuses to slow
21
Ag
Ia
IIa
IIIb IV b Vb V Ib V IIb V III Ib IIb
IIIa IVa Va V Ia V IIa
V III
Zn
Cd In
N
Sb
S
Se
Te
Cl
Br
I
As33
15
7
H
B e
M g
C a S c T i
S r Y
V C r M n
Z r N b M o T c
F e C o N i
R u R h P d
B
A l
G a
C
S i
G e
S n
P
O F
H e
N e
A r
K r
X e
C u
4
12
20 21 22 23 24 25 26 27 28 29 30 31
13
5
32
14
6
34
16
8
35
17
9
36
18
10
2
38 39 40 41 42 43 44 45 46 47 48 49 50 51 53 54
Li
Rb
Na
K
1
3
11
19
37
Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu58 59 60 61 62 63 64 65 66 67 68 69 70 71
La57
Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi56 57 72 73 74 75 76 77 78 79 80 81 82 83
Cs55
22
Co diffusion in CdZnTe
CdZnTe
Co diffusion enhanced by Cd atmosphere Box shaped Co profile
0 100 200 300 400 5001010
1011
1012
1013
1014
30 min: vacuum 60 min: Cd atmosphere
conc
entra
tion
(cm
-3)
depth (µm)
Co: 800 K
23
Co diffusion in CdZnTe
Te rich (p-type ): low mobility incorporation as CoCd ?
Cd rich (n-type): high mobility Co present as Coi
Coi negatively charged ?
0 200 400108
109
1010
1011
1012
1013
1014
conc
entra
tion
(cm
-3)
depth (µm)
0 100 200 300 400 5001010
1011
1012
1013
1014
30 min: vacuum 60 min: Cd atmosphere
conc
entra
tion
(cm
-3)
depth (µm)
Ag: 828 K
n pn p
Co: 800 K
24
n p
Ni diffusion in CdZnTe
Ni diffusion behaves similar to Co diffusion
CdZnTe
0 200 4001010
1011
1012
1013
1014
30 min: vacuum60 min: Cd amosphere
conc
entra
tion
(cm
-3)
depth (µm)
Ni: 800K
25
Summary
• Up hill diffusion for different elements• Up hill diffusion in different semiconductors
Ag
Ia
IIa
IIIb IV b V b V Ib V IIb V III Ib IIb
IIIa IVa Va V Ia V IIa
V III
Zn
Cd In
N
Sb
S
Se
Te
Cl
Br
I
As33
15
7
H
B e
M g
C a S c T i
S r Y
V C r M n
Z r N b M o T c
F e C o N i
R u R h P d
B
A l
G a
C
S i
G e
S n
P
O F
H e
N e
A r
K r
X e
C u
4
12
20 21 22 23 24 25 26 27 28 29 30 31
13
5
32
14
6
34
16
8
35
17
9
36
18
10
2
38 39 40 41 42 43 44 45 46 47 48 49 50 51 53 54
Li
Rb
Na
K
1
3
11
19
37
Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu58 59 60 61 62 63 64 65 66 67 68 69 70 71
La57
Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi56 57 72 73 74 75 76 77 78 79 80 81 82 83
Cs55