Strain relaxation near high-k/Si interface by post-deposition annealing T. Emoto a, * , K. Akimoto b , Y. Yoshida b , A. Ichimiya b , T. Nabatame c , A. Toriumi d,e a Toyota National College of Technology, 2-1 Eisei-cho, Toyota, Aichi 471-8525, Japan b Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan c MIRAI-ASET, AIST Tsukuba West, Tsukuba, Ibaraki 305-8569, Japan d MIRAI-ASRC, AIST Tsukuba Central 4, Tsukuba, Ibaraki 305-8562, Japan e University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan Received 31 May 2004; accepted 18 October 2004 Available online 11 January 2005 Abstract We studied the effect of post-deposition annealing on a HfO 2 /Si interface of by extremely asymmetric X-ray diffraction. Comparing the rocking curves before annealing the sample with those of the annealed sample, it is found that an interfacial layer with a density of 3 g/cm 3 grows at the interface between the HfO 2 layer and the substrate during post-deposition annealing. The wavelength dependency of the integrated intensities of the rocking curve for the as-deposited sample fluctuated with the observation position. This fluctuation was suppressed by annealing. From these results we concluded that the strain introduced into the substrate becomes homogeneous by annealing. Moreover, a quantitative estimation of the strain by curve fitting reveals the existence of compressive strain under the HfO 2 layer. # 2004 Elsevier B.V. All rights reserved. Keywords: High-k; HfO 2 ; Strain; Interfacial layer; Post-deposition anneal 1. Introduction The structure of the interface between an insulator film and semiconductor substrate is an important feature of devices, because the strain introduced into the substrate or defects at the interface may affect the mobility of carriers. Recently, many efforts have been made to realize a metal-oxide-semiconductor (MOS) device using a high-k film as insulator layer. It is well known that HfO 2 is one of the material satisfying the conditions required of insulating layers for next generation silicon devices: a high dielectric constant, thermo- dynamical stability on silicon, and a high dielectric breakdown field. Therefore, the structure of HfO 2 , the structure of the interface between HfO 2 and the Si substrate, and the chemical state of the HfO 2 layer were studied by many methods [1–6]. www.elsevier.com/locate/apsusc Applied Surface Science 244 (2005) 55–60 * Corresponding author. Tel.: +81 565 36 5802; fax: +81 565 36 5825. E-mail address: emoto@toyota-ct.ac.jp (T. Emoto). 0169-4332/$ – see front matter # 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.apsusc.2004.10.088