Thermal Stability of Stacked High-κ Dielectrics on Silicon and Its Improvement by Helium Annealing

Kouichi MURAOKA

Thermal Stability of Stacked High-κ Dielectrics on Silicon and Its Improvement by Helium Annealing

Kouichi MURAOKA

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Thermal stability of stacked high-κ dielectrics, especially ZrO₂, HfO₂ and ZrSiO₄/SiO₂ layered structures, on silicon has been investigated in terms of ultrahigh vacuum (UHV), 1 Torr N₂ and helium (He) gas annealing with controlled oxygen partial pressure (P_O₂) at 920. Comparison of 2 nm and 20 nm ZrO₂ films under UHV annealing revealed that the trigger of silicidation is the contact of ZrO₂, SiO and Si accompanying disappearance of interfacial SiO₂ layer due to SiO desorption. In the contact position, a small amount of SiO gas can easily change ZrO₂ to ZrSi₂. This reaction model is also applicable to the silicidation of HfO₂ and ZrSiO₄, at not only stacked high-κ film/Si substrate interface, but also at gate poly-Si/high-κ film interface. Moreover, comparison of UHV, N₂ and He annealing with controlled P_O₂ revealed that the optimal P_O₂ ranges in He at which the thermal stability of layered structure can be achieved are wider than those in UHV and N₂. This result suggests that He gas physically may obstruct SiO creation due to the quenching of atomic vibration at degradation-prone sites in the SiO₂/Si interface, thus reducing probability of bond breaking process, which is the first step of silicidation.

Publication: IEICE TRANSACTIONS on Electronics Vol.E87-C No.1 pp.9-16

Publication Date: 2004/01/01

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Type of Manuscript: Special Section PAPER (Special Section on High-κ Gate Dielectrics)

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Kouichi MURAOKA, "Thermal Stability of Stacked High-κ Dielectrics on Silicon and Its Improvement by Helium Annealing" in IEICE TRANSACTIONS on Electronics, vol. E87-C, no. 1, pp. 9-16, January 2004, doi: .
Abstract: Thermal stability of stacked high-κ dielectrics, especially ZrO₂, HfO₂ and ZrSiO₄/SiO₂ layered structures, on silicon has been investigated in terms of ultrahigh vacuum (UHV), 1 Torr N₂ and helium (He) gas annealing with controlled oxygen partial pressure (P_O₂) at 920. Comparison of 2 nm and 20 nm ZrO₂ films under UHV annealing revealed that the trigger of silicidation is the contact of ZrO₂, SiO and Si accompanying disappearance of interfacial SiO₂ layer due to SiO desorption. In the contact position, a small amount of SiO gas can easily change ZrO₂ to ZrSi₂. This reaction model is also applicable to the silicidation of HfO₂ and ZrSiO₄, at not only stacked high-κ film/Si substrate interface, but also at gate poly-Si/high-κ film interface. Moreover, comparison of UHV, N₂ and He annealing with controlled P_O₂ revealed that the optimal P_O₂ ranges in He at which the thermal stability of layered structure can be achieved are wider than those in UHV and N₂. This result suggests that He gas physically may obstruct SiO creation due to the quenching of atomic vibration at degradation-prone sites in the SiO₂/Si interface, thus reducing probability of bond breaking process, which is the first step of silicidation.
URL: https://global.ieice.org/en_transactions/electronics/10.1587/e87-c_1_9/_p

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@ARTICLE{e87-c_1_9,
author={Kouichi MURAOKA, },
journal={IEICE TRANSACTIONS on Electronics},
title={Thermal Stability of Stacked High-κ Dielectrics on Silicon and Its Improvement by Helium Annealing},
year={2004},
volume={E87-C},
number={1},
pages={9-16},
abstract={Thermal stability of stacked high-κ dielectrics, especially ZrO₂, HfO₂ and ZrSiO₄/SiO₂ layered structures, on silicon has been investigated in terms of ultrahigh vacuum (UHV), 1 Torr N₂ and helium (He) gas annealing with controlled oxygen partial pressure (P_O₂) at 920. Comparison of 2 nm and 20 nm ZrO₂ films under UHV annealing revealed that the trigger of silicidation is the contact of ZrO₂, SiO and Si accompanying disappearance of interfacial SiO₂ layer due to SiO desorption. In the contact position, a small amount of SiO gas can easily change ZrO₂ to ZrSi₂. This reaction model is also applicable to the silicidation of HfO₂ and ZrSiO₄, at not only stacked high-κ film/Si substrate interface, but also at gate poly-Si/high-κ film interface. Moreover, comparison of UHV, N₂ and He annealing with controlled P_O₂ revealed that the optimal P_O₂ ranges in He at which the thermal stability of layered structure can be achieved are wider than those in UHV and N₂. This result suggests that He gas physically may obstruct SiO creation due to the quenching of atomic vibration at degradation-prone sites in the SiO₂/Si interface, thus reducing probability of bond breaking process, which is the first step of silicidation.},
keywords={},
doi={},
ISSN={},
month={January},}

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TY - JOUR
TI - Thermal Stability of Stacked High-κ Dielectrics on Silicon and Its Improvement by Helium Annealing
T2 - IEICE TRANSACTIONS on Electronics
SP - 9
EP - 16
AU - Kouichi MURAOKA
PY - 2004
DO -
JO - IEICE TRANSACTIONS on Electronics
SN -
VL - E87-C
IS - 1
JA - IEICE TRANSACTIONS on Electronics
Y1 - January 2004
AB - Thermal stability of stacked high-κ dielectrics, especially ZrO₂, HfO₂ and ZrSiO₄/SiO₂ layered structures, on silicon has been investigated in terms of ultrahigh vacuum (UHV), 1 Torr N₂ and helium (He) gas annealing with controlled oxygen partial pressure (P_O₂) at 920. Comparison of 2 nm and 20 nm ZrO₂ films under UHV annealing revealed that the trigger of silicidation is the contact of ZrO₂, SiO and Si accompanying disappearance of interfacial SiO₂ layer due to SiO desorption. In the contact position, a small amount of SiO gas can easily change ZrO₂ to ZrSi₂. This reaction model is also applicable to the silicidation of HfO₂ and ZrSiO₄, at not only stacked high-κ film/Si substrate interface, but also at gate poly-Si/high-κ film interface. Moreover, comparison of UHV, N₂ and He annealing with controlled P_O₂ revealed that the optimal P_O₂ ranges in He at which the thermal stability of layered structure can be achieved are wider than those in UHV and N₂. This result suggests that He gas physically may obstruct SiO creation due to the quenching of atomic vibration at degradation-prone sites in the SiO₂/Si interface, thus reducing probability of bond breaking process, which is the first step of silicidation.
ER -