TY - JOUR
T1 - Characterization of flatband voltage roll-off and roll-up behavior in La2O3/silicate gate dielectric
AU - Kakushima, K.
AU - Koyanagi, T.
AU - Tachi, K.
AU - Song, J.
AU - Ahmet, P.
AU - Tsutsui, K.
AU - Sugii, N.
AU - Hattori, T.
AU - Iwai, H.
N1 - Funding Information:
This work was supported by NEDO. The synchrotron radiation experiments were performed at the BL47XU in the SPring-8 with the approval of the Japan Synchrotron Radiation Research Institute (JASRI) (Proposal No. 2009A1754).
Copyright:
Copyright 2011 Elsevier B.V., All rights reserved.
PY - 2010/7
Y1 - 2010/7
N2 - The roll-off and roll-up behavior of flatband voltage (Vfb) on equivalent oxide thickness (EOT) of La2O3/silicate capacitors have been characterized by X-ray photoelectron spectroscopy and modeled by the fixed charges. It has been revealed that the thickness of the reactively formed silicate layer is dependent on the La2O3 thickness initially deposited on the wafer. When the La2O 3 thickness is over 3 nm, the silicate layer has been found to be formed with a constant thickness of 1.6 nm. However, while decreasing the La2O3 thickness to 1 nm, the thickness of silicate layer decreases due to the reduction of radical oxygen atoms originated from the La2O3 layer, resulting in the formation of La-rich silicate. The Vfb roll-off behavior can be attributed to the enhanced generation of positive fixed charges induced by the diffusion of metal atoms from the gate electrode into the silicate layer. On the other hand, the V fb roll-up behavior can be explained when the initially deposited La2O3 layer has been all converted into silicate.
AB - The roll-off and roll-up behavior of flatband voltage (Vfb) on equivalent oxide thickness (EOT) of La2O3/silicate capacitors have been characterized by X-ray photoelectron spectroscopy and modeled by the fixed charges. It has been revealed that the thickness of the reactively formed silicate layer is dependent on the La2O3 thickness initially deposited on the wafer. When the La2O 3 thickness is over 3 nm, the silicate layer has been found to be formed with a constant thickness of 1.6 nm. However, while decreasing the La2O3 thickness to 1 nm, the thickness of silicate layer decreases due to the reduction of radical oxygen atoms originated from the La2O3 layer, resulting in the formation of La-rich silicate. The Vfb roll-off behavior can be attributed to the enhanced generation of positive fixed charges induced by the diffusion of metal atoms from the gate electrode into the silicate layer. On the other hand, the V fb roll-up behavior can be explained when the initially deposited La2O3 layer has been all converted into silicate.
KW - Hard X-ray photoelectron spectroscopy
KW - High-k gate dielectric
KW - Lanthanum oxide
KW - Silicate
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U2 - 10.1016/j.sse.2010.03.007
DO - 10.1016/j.sse.2010.03.007
M3 - Article
AN - SCOPUS:77955317047
VL - 54
SP - 720
EP - 723
JO - Solid-State Electronics
JF - Solid-State Electronics
SN - 0038-1101
IS - 7
ER -