Interface and plasma damage analysis of PEALD TaCN deposited on HfO₂ for advanced CMOS studied by angle resolved XPS and C-V

详细信息    查看全文

• 作者：Fabien Piallat^a ; ^b ; ^c ; ^{fabien.piallat@cea.fr" class="auth_mail} ; Virginie Beugin^b ; Remy Gassilloud^b ; Laurent Dussault^c ; Bernard Pelissier^c ; Charles Leroux^b ; Pierre Caubet^a ; Christophe Vallé ; e^c
• 关键词：XPS ; Metal gate ; Tantalum ; Interface ; Hafnium ; High-k dielectric
• 刊名：Applied Surface Science
• 出版年：1 June, 2014
• 年：2014
• 卷：303
• 期：Complete
• 页码：388-392
• 全文大小：620 K

文摘

Plasma enhanced atomic layer deposition (PEALD) TaCN deposited on HfO₂ was studied by X-ray photoelectron spectroscopy (XPS) to understand the reactions taking place at the interface and connect them with C-V electrical characteristics of MOS devices. Moreover, angular resolved XPS (AR-XPS) was used for composition depth profiling of TaCN/HfO₂/SiO₂/Si stacks. Clear oxidation of the metal electrode through Taript>ript>O bonding formation and migration of N in the dielectric with Hfript>ript>N are shown. These modifications of chemical bonding give an insight on the electrical results. Low equivalent oxide thicknesses (EOT), as low as 0.89 nm and current leakage improvement by more than 5 decades, are observed for deposition with low plasma power and can be related to HfN content in HfO₂ layer. The increase of plasma power used for TaCN deposition results in densification of the layer and promotes the creation of TaC in TaCN material. However H₂ plasma has an impact on HfO₂ with a reduction and scattering of the measured current leak gain. TaCN/HfO₂ interface is also impacted with further creation of TaO_x, leading to an increase of EOT when plasma power is increased. Based on these findings, reaction mechanisms with the corresponding Gibbs free energy are proposed.