Transcript Document

Novel high-k materials
Can we nominate candidates for the 22 and the 16 nm nodes?
Olof Engstrom
Chalmers University of Technology
Paul Hurley
Tyndall National Institute
Octavian Buiu
University of Liverpool
Max Lemme
AMO
Outline
•
•
•
•
•
Why high-k?
Essential properties needed
Why are rare-earth oxides interesting?
Comparison between different candidates
Finalists?
Bulk MOS: Oxide voltage vs gate voltage
Oxide thickness= 10 [Å] Silicon doping: 4 1018 cm-3
k
3.9
7
15
25
O
0.6
S
qYs
V
EF
Oxide voltage [V]
M
0.4
0.2
0
-0.2
0
0.5
1
Gate voltage [v]
1.5
The k-value should be ”lagom”
SiO2
For Lg = 70 nm
k = 10
k = 25
k = 50
F
Mohapatra et al, IEEE Trans. Electron. Dev. 49, 826 (2002)
Essential properties
DEc
DEv
•k-values
•Energy offsets DEc and DEv
•Reactivity with silicon
•Hygroscopicity
•Structural stability
•Interface states
•Charge carrier traps
Metals of interest
Group**
1
IA
1A
18
VIIIA
1
1
H
1.008
3
2
11
4
6
7
9.012
12
Na Mg
22.99
24.31
19
20
5
6
7
8
B
C
N
O
10.81 12.01 14.01 16.00
8
9
10
3
4
5
6
7
11
------VIII
----IIIB IVB VB VIB VIIB
IB
-3B 4B 5B 6B 7B
1B
------- 8 ------21
22
23
24
25
26
27
28
29
12
IIB
2B
30
13
14
Al Si
15
16
P
S
26.98 28.09 30.97 32.07
31
32
33
34
2
He
9
4.003
10
F
Ne
19.00
20.18
17
18
Cl Ar
35.45
39.95
35
36
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
39.10
37
5
4
Li Be
6.941
3
8A
13
14
15
16
17
IIIA IVA VA VIA VIIA
3A 4A 5A 6A
7A
2
IIA
2A
40.08
38
Rb Sr
85.47
87.62
55
56
87
88
44.96 47.88 50.94 52.00 54.94 55.85 58.93 58.69 63.55
39
40
41
42
43
44
45
46
47
65.39
48
69.72 72.59 74.92 78.96
49
50
51
52
Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te
88.91 91.22 92.91 95.94
57
72
73
74
(98)
101.1 102.9 106.4 107.9
112.4
75
76
77
78
79
80
107
108
109
110
111
112
114.8 118.7 121.8 127.6
81
82
83
84
79.90
53
83.80
54
I
Xe
126.9
131.3
85
86
Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
132.9 137.3 *138.9 178.5 180.9 183.9 186.2 190.2 190.2 195.1 197.0 200.5 204.4 207.2 209.0 (210) (210) (222)
89
104
105
106
Fr Ra Ac Rf Db Sg Bh Hs Mt Ds Uuu Uub
(223) (226) ~(227) (257) (260) (263) (262) (265) (266) (271) (272) (277)
Lanthanide
Series*
Actinide
Series~
58
59
60
61
62
63
64
65
66
67
68
114
116
118
Uuq
Uuh
Uuo
(296)
(298)
(?)
69
70
71
Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
140.1 140.9 144.2 (147) 150.4 152.0 157.3 158.9 162.5
90
91
92
93
94
95
96
97
98
164.9
99
167.3 168.9 173.0 175.0
100
101
102
103
Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr
232.0 (231) (238) (237) (242)
(243)
(247) (247) (249)
(254)
(253)
(256) (254) (257)
** Groups are noted by 3 notation conventions.
Polarizability and k-value
Clausius-Mosotti
2

4
]
3
V
m
k
1

[1  4
]
3
V
m
[1 
Polarizability, 
6
5
4
3
2
1
0
Si(4+) Al(3+) Hf(4+) Zr(4+) Y(3+) La(3+)Ce(3+) Pr(3+)Gd(3+)Yb(3+) Lu(3+)
Ion
D. G. Schlom et al, Thin films and heterostructures for oxide electronics, (Springer, 2005), p. 31
Energy offset vs. k-value
Borders for the 22 nm
LSTP bulk node:
10-2 A/cm2
EOT=0.6 nm
Vox= 1V
(Target)
LaLuO3
Requires k DE ≈ 70 eV
O. Engström, B. Raeissi, S. Hall, O. Buiu, M.C. Lemme, H.D.B. Gottlob, P.K. Hurley, K. Cherkaoui, SSE, 51, 622 (2007)
Reactivity
La2O3 (evap)
Gd2O3 (MBE)
Kim et al
SSE 49, 825
(2005)
Czernohorsky et al
APL 88, 152905 (2006)
As grown
Lu2O3 (ALD)
Scham et al
Topics in Appl. Phys.
Vol. 106, p. 153
(Springer, 2007)
550 C
950 C
Reactivity
Si + MO
DG1000C
For Si + O
DG1000C < 0
M + SiO2
MSi + SiO2
M + MSiO
500
DG [kJ/mol]
400
DG1000C
300
200
100
SiO2
0
Al2O3 ZrO2
HfO2 Yb2O3 Lu2O3 Gd2O3 Dy2O3 Sm2O3 Pr2O3 La2O3
Oxide
D. G. Schlom et al, Thin films and heterostructures for oxide electronics, (Springer, 2005), p. 31
EOT (120 hrs)/EOT (fresh)
Hygroscopicity
1000
J120 hrs/Jfresh
100
10
1
0,1
0,01
1E-3
Eu2O3
ZrO2
Yb2O3 Lu2O3 Gd2O3 Dy2O3 Sm2O3 Pr2O3 La2O3
2,5
2,0
1,5
1,0
0,5
0,0
SiO2
ZrO2
Oxide
Oxide
water + oxide
Yb2O3 Lu2O3 Gd2O3 Dy2O3 Sm2O3 Pr2O3 La2O3
hydroxide
K.Kakushima, K.Tsutsui, S-I. Ohmi, P.Ahmet V.R. Rao and H. Iwai in Rare earth oxide thin films ( Springer, 2007), p. 345
Structural stability
Example: LaLuO3
APL, 89, 222902 (2006)
Leakage
Leakage current [A/cm2]
1
Gd2O3 [2], HfO2[1], ZrO2[1]
0,1
0,01
HfGdO [3]
1E-3
1E-4
3
1E-5
HfO2 [5]
1E-6
Lu2O3 [4]
1E-7
with epitaxial
Lu2O3 - silicate IL)
HfO2
(with HfSiO IL)
and
ZrO2
La2O3 [1]
1E-8
1E-9
0,4
0,6
0,8
1,0
1,2
1,4
EOT [nm]
[1] H. Iwai et al, Proc. IEDM, 2002
[2] H.D.B. Gottlob et al, IEEE Electron Dev. Lett. 27, 814 (2006)
[3] S. Govindarajan et al, APL 91, 062906 (2007)
[4] P. Darmawan et al, APL 91, 092903 (2007)
[5] A. Ogawa et al Microel. Eng. 84, 1861 (2007)
1,6
Experimental C = f (V,freq.)
Gd2O3
ALD
HfO2
React.
sputt.
Gd2O3
MBE
B.Raeissi, J.Piscator, O.Engström, S.Hall, O.Buiu, M.C.Lemme, H.D.B.Gottlob, P.Hurley, K.Cerkaoui and H.J.Osten,
Proc. ESSDERC, 2007, p 287
LaSiOx/Si interface
LaSiOx
Wafer X3361-19
Site 19a18
0.030
2
Capacitance (F/m )
0.025
0.020
0.015
LaSiOx
E-beam
evap.
0.010
1 kHz
10 kHz
100 kHz
1 MHz
0.005
0.000
-2
-1
0
1
Voltage Vg (V)
P.K.Hurley, K.Cherkaoui, E.O’Connor, M.C.Lemme, H. D.B. Gottlob, M.Schmidt , S.Hall, Y.Lu, O.Buiu,
B.Raeissi, J. Piscator and O.Engstrom, J. Electrochem. Soc., in press
Dit for HfO2, Gd2O3 and LaSiOx
10
0.0035
LaSiOx 4 nm EOT
Gp/
12
-2
-1
Dit (x10 cm eV )
Gp/
0.0030
8
12
0.0025
0.0020
6
4
0.09 eV
-1
0.92
0.83
-2
Dit=5x10 eV cm
Vg=-0.75V
0.0015
10000

100000
1000000
HfO2 ALD 1.4nm EOT (Sample 1)
HfO2 sputtered 18nm EOT (Sample 4)
Gd2O3 MOCVD 17nm EOT (Sample 5)
Gd2O3 ALD 13.5nm EOT (Sample 6)
2
0,4
LaSiOx e-beam 4nm EOT (Sample 9)
0,6
0,8
1,0
E-Ev (eV)
P.K.Hurleya, K.Cherkaoui, E.O’Connor, M.C.Lemme, H. D.B. Gottlob, M.Schmidt , S.Hall, Y.Lu, O.Buiu,
B.Raeissi, J. Piscator and O.Engstrom, J. Electrochem. Soc., in press
Final solution: The Nominees
Group**
1
IA
1A
18
VIIIA
1
1
H
1.008
3
2
11
4
6
7
9.012
12
Na Mg
22.99
24.31
19
20
21
22
23
24
25
26
27
28
29
12
IIB
2B
6
7
8
9
4.003
10
B
C
N
O
F
Ne
19.00
20.18
17
18
30
13
14
Al Si
15
16
P
S
26.98 28.09 30.97 32.07
31
32
33
34
40.08
38
Rb Sr
85.47
87.62
55
56
87
88
44.96 47.88 50.94 52.00 54.94 55.85 58.93 58.69 63.55
39
40
41
42
43
44
45
46
47
65.39
48
69.72 72.59 74.92 78.96
49
50
51
52
Cl Ar
35.45
39.95
35
36
Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te
88.91 91.22 92.91 95.94
57
72
73
74
(98)
101.1 102.9 106.4 107.9
112.4
75
76
77
78
79
80
107
108
109
110
111
112
114.8 118.7 121.8 127.6
81
82
83
84
79.90
53
83.80
54
I
Xe
126.9
131.3
85
86
Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
132.9 137.3 *138.9 178.5 180.9 183.9 186.2 190.2 190.2 195.1 197.0 200.5 204.4 207.2 209.0 (210) (210) (222)
89
104
105
106
Fr Ra Ac Rf Db Sg Bh Hs Mt Ds Uuu Uub
(223) (226) ~(227) (257) (260) (263) (262) (265) (266) (271) (272) (277)
Lanthanide
Series*
Actinide
Series~
58
59
60
61
62
63
64
65
66
67
68
114
116
118
Uuq
Uuh
Uuo
(296)
(298)
(?)
69
70
71
Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
140.1 140.9 144.2 (147) 150.4 152.0 157.3 158.9 162.5
90
91
92
93
94
95
96
97
98
164.9
99
167.3 168.9 173.0 175.0
100
101
102
103
Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr
232.0 (231) (238) (237) (242)
(243)
(247) (247) (249)
(254)
(253)
(256) (254) (257)
** Groups are noted by 3 notation conventions.
Nominees
He
5
10.81 12.01 14.01 16.00
8
9
10
3
4
5
6
7
11
------VIII
----IIIB IVB VB VIB VIIB
IB
-3B 4B 5B 6B 7B
1B
------- 8 -------
2
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
39.10
37
5
4
Li Be
6.941
3
8A
13
14
15
16
17
IIIA IVA VA VIA VIIA
3A 4A 5A 6A
7A
2
IIA
2A
Too low
k DEc,v
Wild cards
Exists only in
Andromeda
Finalists
Pr2O3
La2O3
Gd2O3
LaLuO3
HfO2
ZrO2
k x DEc
66
69
42
67
35
38
k x DEv
Low
66
31
67
83
80
Reactivity
High
High
Low
High
High
High
Hygroscop.
Low
High
High
Low
Low
Low
Struct. stab.
Low
Low
High
High
Low
Low
Conclusion
Lantanum based oxides seem
worth a bid
but fortunately for academic people
there is a lot more work to do!
C [F]
Theoretical C=f(V,freq.)
2.5
10
2
10
1.5
10
1
10
5
10
-9
2
10
1.5
10
1
10
-9
-9
-9
-9
-9
-10
5
10
-10
0
-0.25
0
0.25
0.5
0.75
1
C-V
-9
0
1.25
0
0.2
0.4
0.6
0.8
1
Dit [m-2eV-1]
Gate voltage [V]
7
10
6
10
5
4
3
10
10
10
17
17
17
17
17
3
10
2.5
10
2
10
1.5
10
1
10
5
10
17
17
17
17
Dit = f(DGn)
17
16
0
0
0.1
0.2
0.3
0.4
0.5
DGn[eV]
0
0.1
0.2
0.3
0.4
0.5
-20
sn [m2]
-21
log sn = f(DGn)
-20.5
-22
-21
-23
-21.5
-24
-22
0
0.1
0.2
0.3
0.4
0.2
DGn[eV]
0.25
0.3
0.35
0.4
The concept of polarization
F = V/d
P/(3e0)
Floc= F + P/(3e0)
P = (1/Vm) c Floc
4e0 c [A3]
Remote
phonon
scattering
Large
 means
sloppier
material
(spring
+
constant/mass)1/2
HfO2
Oxide
-
ZrSiO4
ZrO2
Al2O3
SiO2
0,00
0,05
0,10
0,15
0,20
0,25
0,30
Fröhlich coupling constant
High-k
oxide
Fischetti et al, PRB 90, 4587 (2001)
LO-phonon
Si