Atomic Layer Deposition of HfO2 Thin Films on Ultrathin SiO2 Formed by Remote Plasma Oxidation

다국어 초록 (Multilingual Abstract)

An ultrathin SiO₂ layer was grown on a H-terminated Si substrate by
using remote plasma oxidation. The subsequent HfO₂ deposition on the
ultrathin SiO₂ was achieved by a remote plasma atomic layer
deposition (RPALD). During the HfO₂ film deposition and rapid
thermal annealing (RTA), the ultrathin SiO₂ buffer layer effectively
suppressed the formation of Hf silicate layers in the interfacial
region. The Hf silicate layer in the interfacial region grew with
increasing RTA temperature. The positive fixed oxide charges in the
HfO₂ film were reduced with increasing RTA temperature. The
thickness of the HfO₂ films with an ultrathin SiO₂ buffer layer
showed a lower effective fixed oxide charge density (Qf,eff) due to
the shift of the flat band voltage (VFB) toward the positive
direction, compared to those with H-terminated Si. The thin
interfacial layer of the HfO₂ films with a thin SiO₂ buffer layer
resulted in a low equivalent oxide thickness (EOT) value. The
leakage current densities of the HfO₂ films increased because of the
crystallization of the HfO₂ film after RTA.

다국어 초록 (Multilingual Abstract)

An ultrathin SiO₂ layer was grown on a H-terminated Si substrate by
using remote plasma oxidation. The subsequent HfO₂ deposition on the
ultrathin SiO₂ was achieved by a remote plasma atomic layer
deposition (RPALD). During the HfO₂ film deposition and rapid
thermal annealing (RTA), the ultrathin SiO₂ buffer layer effectively
suppressed the formation of Hf silicate layers in the interfacial
region. The Hf silicate layer in the interfacial region grew with
increasing RTA temperature. The positive fixed oxide charges in the
HfO₂ film were reduced with increasing RTA temperature. The
thickness of the HfO₂ films with an ultrathin SiO₂ buffer layer
showed a lower effective fixed oxide charge density (Qf,eff) due to
the shift of the flat band voltage (VFB) toward the positive
direction, compared to those with H-terminated Si. The thin
interfacial layer of the HfO₂ films with a thin SiO₂ buffer layer
resulted in a low equivalent oxide thickness (EOT) value. The
leakage current densities of the HfO₂ films increased because of the
crystallization of the HfO₂ film after RTA.

참고문헌 (Reference)

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10 G. D. Wilk, 89 : 5243-, 2001

11 M. Ritala, 288 : 319-, 2000

12 M.-H. Cho, 81 : 472-, 2002

13 Y. Kim, 92 : 5443-, 2002

14 Woonyoung Lee, "Characteristics of Plasma Enhanced-Atomic Layer Deposition (PE-ALD) SnO2 Thin Film" 한국물리학회 46 (46): 756-759, 2005

15 Jaehyoung Koo, "Characteristics of Hafnium-Aluminum-Oxide Thin Films Deposited by Using Atomic Layer Deposition with Various Aluminum Compositions" 한국물리학회 47 (47): 501-507, 2005

16 Hyoungsub Kim, "Atomic Layer Deposition of Ultrathin Metal-Oxide Films for Nano-Scale Device Applications" 한국물리학회 48 (48): 5-17, 2006

17 Y. Roh, "A Study on Interface Layer with Annealing Conditions ZrO2/ZrSixOy High-k Gate Oxide" 한국물리학회 49 (49): 755-759, 2006