It is shown that the well-known negative flatband voltage (VFB) shift, induced by rare-earth oxide capping in metal gate stacks, can be completely reversed in the absence of the silicon overlayer. Using TaN metal gates and Gd2O3-doped dielectric, we measure a ∼350 mV negative shift with the Si overlayer present and a ∼110 mV positive shift with the Si overlayer removed. This effect is correlated to a positive change in the average electrostatic potential at the TaN/dielectric interface which originates from an interfacial dipole. The dipole is created by the replacement of interfacial oxygen atoms in the HfO2 lattice with nitrogen atoms from TaN.

1.
J. K.
Schaeffer
,
L. R. C.
Fonseca
,
S. B.
Samavedam
,
Y.
Liang
,
P. J.
Tobin
, and
B. E.
White
,
Appl. Phys. Lett.
85
(
10
),
1826
(
2004
).
2.
H. C.
Wen
,
P.
Majhi
,
K.
Choi
,
C. S.
Park
,
H. N.
Alshareef
,
H. R.
Harris
,
H.
Luan
,
H.
Niimi
,
H. B.
Park
,
G.
Bersuker
 et al,
Microelectron. Eng.
85
(
1
),
2
(
2008
).
3.
J. R.
Hauser
,
NCSU Software, Version 5.0
,
Department of Electrical and Computer Engineering, NC State University
,
Raleigh, NC
,
2000
.
4.
K.
Kakushima
,
K.
Okamoto
,
M.
Adachi
,
K.
Tachi
,
P.
Ahmet
,
K.
Tsutsui
,
N.
Sugii
,
T.
Hattori
, and
H.
Iwai
,
Solid-State Electron.
52
(
9
),
1280
(
2008
).
5.
Y.
Yamamoto
,
K.
Kita
,
K.
Kyuno
, and
A.
Toriumi
,
Jpn. J. App. Phys.
46
,
7251
(
2007
).
6.
P. D.
Kirsch
,
P.
Sivasubramani
,
J.
Huang
,
C. D.
Young
,
M. A.
Quevedo-Lopez
,
H. C.
Wen
,
H.
Alshareef
,
K.
Choi
,
C. S.
Park
,
K.
Freeman
 et al,
Appl. Phys. Lett.
92
(
9
),
092901
(
2008
).
7.
H. N.
Alshareef
,
J. A.
Caraveo-Frescas
, and
D. K.
Cha
,
Appl. Phys. Lett.
97
(
20
),
202108
(
2010
).
8.
J.
Robertson
,
Eur. Phys. J.: Appl. Phys.
28
(
03
),
265
(
2004
).
9.
L.
Lin
and
J.
Robertson
,
Microelectron. Eng.
86
(
7–9
),
1743
(
2009
).
10.
E.
Cartier
,
M.
Hopstaken
, and
M.
Copel
,
Appl. Phys. Lett.
95
(
4
),
042901
(
2009
).
11.
C. L.
Hinkle
,
R. V.
Galatage
,
R. A.
Chapman
,
E. M.
Vogel
,
H. N.
Alshareef
,
C.
Freeman
,
E.
Wimmer
,
H.
Niimi
,
A.
Li-Fatou
,
J. B.
Shaw
 et al,
Appl. Phys. Lett.
96
(
10
),
103502
(
2010
).
12.
E.
Wimmer
,
R.
Najafabadi
,
G. A.
Young
, Jr.
,
J. D.
Ballard
,
T. M.
Angeliu
,
J.
Vollmer
,
J. J.
Chambers
,
H.
Niimi
,
J. B.
Shaw
,
C.
Freeman
 et al,
J. Phys.: Condens. Matter
22
,
384215
(
2010
).
13.
G.
Kresse
and
D.
Joubert
,
Phys. Rev. B
59
,
1758
(
1999
).
14.
J. P.
Perdew
,
M.
Ernzerhof
, and
K.
Burke
,
J. Chem. Phys.
105
,
9982
(
1996
).
15.
P. E.
Blochel
,
Phys. Rev. B
50
,
17953
(
1994
).
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