Removal of Interfacial Layer in HfO2 Gate Stack by Post-Gate Cleaning Using NF3/NH3 Dry Cleaning Technique

Min Seon Lee; Hoon Jung Oh; Joo Hee Lee; In Geun Lee; Woo Gon Shin; Sung Yong Kang; Dae Hong Ko

doi:10.4028/www.scientific.net/SSP.219.11

Paper Titles

Preface, Committee and Acknowledgement

Necessity of Cleaning and its Application in Future Memory Devices
p.3

Removal of Interfacial Layer in HfO₂ Gate Stack by Post-Gate Cleaning Using NF₃/NH₃ Dry Cleaning Technique
p.11

Catalyst Assisted Low Temperature Pre Epitaxial Cleaning for Si and SiGe Surfaces
p.16

HF-Last Wet Clean in Combination with a Low Temperature GeH₄-Assisted HCl In Situ Clean Prior to Si_0.8Ge_0.2-on-Si Epitaxial Growth
p.20

Retardation Phenomenon of Oxide Removal during the Formation of Dual Gate Oxide via PR-Mask Wet Etching
p.24

Aluminum Reduction in SC1
p.28

Metal Removal Efficiency in Deep Submicron Trenches by Wet Chemicals
p.32

Impact of Surface Treatment of Si₃N₄ on Subsequent SiO₂ Deposition
p.36

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Removal of Interfacial Layer in HfO₂ Gate Stack by Post-Gate Cleaning Using NF₃/NH₃ Dry Cleaning Technique

Abstract:

HfO₂ gate stack has been one of the most popular subjects of research in recent years due to its outstanding material properties, such as high-k (20~25), wide band gap (~5.68eV), and the compatibility with Si-based semiconductor process technology. However, the interfacial layer (IL) with a reduced k-value between HfO₂ dielectric and Si channel is still a critical issue for future ultra large scale integration (ULSI) technology application of the HfO₂ gate stack. Various ways have been studied to improve the IL properties of HfO₂ gate stack and to achieve ~1nm-thick equivalent oxide thickness (EOT) of the gate stack. Recently, fluorine incorporations into the HfO₂ gate stack have been suggested for improvement of the electrical properties of the gate stack by defect passivation.¹^,² However, it was reported that the SiO_x IL grows during the fluorine treatment of HfO₂ film, which finally led to degradation of electrical characteristics.² In this paper, we present interesting findings on the IL removal effect of fluorine incorporation into the HfO₂ gate stack where a post-gate dry cleaning technique is used with the NF₃/NH₃ plasma.