0167-9317/$ - see front matter Ó 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.mee.2007.04.103 www.elsevier.com/locate/mee Microelectronic Engineering 84 (2007) 2274–2277 Impact of high- and SiO 2 interfacial layer thickness on low- frequency (1/f) noise in aggressively scaled metal gate/HfO 2 n-MOSFETs: role of high- phonons P. Srinivasan a , B. P. Linder b , V. Narayanan b , D. Misra a , E. Cartier b,* a Dept. of Electrical and Computer Engineering, New Jersey Inst. of Tech., Newark, NJ, USA. b IBM Semiconductor Research and Development Center (SRDC), IBM T.J. Watson Research Center, Yorktown Heights, NY 10598, USA Abstract The effect of high- (t HfO2 ) and interfacial layer thickness (t IL ) on the low-frequency (LF) drain current noise is studied in n-MOSFETs with HfO 2 gate oxide and TiN metal gate. While a 1/f type spectrum is observed, the dominant noise mechanism is found to be mobility fluctuations. The variation in Hooge’s parameter H is studied and the results are correlated with channel electron mobility ( ). The physical origin of noise fluctuations is then determined from the comparison. The results show that high- phonon scattering is likely the dominant source for 1/f noise in aggressively scaled HfO 2 -metal gate devices. The devices meet the ITRS specification and the selection of t IL becomes significant for use in analog and mixed signal based applications. Keywords: high-k, metal gates; 1/f noise; phonon scattering; Hooge’s parameter; mobility 1. Introduction Hafnium-based dielectrics with metal gates are the most likely replacement for SiO 2 and poly-Si in future CMOS technologies [1]. However various reliability [2] and gate-integration issues still persist. Reducing Hf-related defects and impurities plays a Corresponding author. Tel.:+ 001-914-945-2435; Fax: +001 914-945-2141. E-mail: ecartier@us.ibm.com (E. Cartier) significant role in enhancing the stability of the gate stack and the device performance. One of the performance metrics and reliability factors is low- frequency noise, particularly for RF and analog circuits. We study here the effect of high- layer thickness (t HfO2 ) and interfacial SiO 2 layer thickness (t IL ) on the low-frequency (LF) drain current noise in n- MOSFETs with HfO 2 gate dielectrics and TiN gate electrodes. The dominant 1/f noise mechanism is determined and the variation in Hooge’s parameter