Origin of flat band voltage shift in HfO2 gate dielectric with La2O3 insertion

The origin of flat band voltage (VFB) shift with La2O3 insertion for HfO2 gate dielectrics has been carefully examined. By separating the effect of the fixed charges located at each interface by thickness-dependent VFB evolution, total voltage shifts (dipole) at metal/high-k and high-k/SiO2 interfac...

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Published inSolid-state electronics Vol. 52; no. 9; pp. 1280 - 1284
Main Authors Kakushima, K., Okamoto, K., Adachi, M., Tachi, K., Ahmet, P., Tsutsui, K., Sugii, N., Hattori, T., Iwai, H.
Format Journal Article Conference Proceeding
LanguageEnglish
Published Oxford Elsevier Ltd 01.09.2008
Elsevier Science
Subjects
Applied sciences
Dielectric, amorphous and glass solid devices
Electronegativity
Electronics
Exact sciences and technology
Flat band voltage
HfO2
High-k
La2O3
Metal gate
Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices
La2O3
Flat band voltage
HfO2
Electronegativity
High-k
Metal gate
Hafnium oxide
Lanthanum oxide
Silicon oxides
Dipole
High k dielectric
Silicon
Capacitor
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Summary:The origin of flat band voltage (VFB) shift with La2O3 insertion for HfO2 gate dielectrics has been carefully examined. By separating the effect of the fixed charges located at each interface by thickness-dependent VFB evolution, total voltage shifts (dipole) at metal/high-k and high-k/SiO2 interfaces have been estimated. Using stacked capacitors of La2O3 and HfO2, it can be concluded that VFB is mainly determined by the high-k on SiO2. Therefore, the dipole at La2O3 and the interface has an additional dipole of 0.36eV compared with that of HfO2/SiO2. The same trend has also been obtained with a high-k on a Si substrate without a SiO2 layer. A simple model using electronegativity has been proposed to explain the VFB shift.
ISSN:0038-1101
1879-2405
DOI:10.1016/j.sse.2008.04.015