Composition spread metal thin film fabrication technique based on ion beam sputter deposition P. Ahmet a, * , T. Nagata a , D. Kukuruznyak a , S. Yagyu a , Y. Wakayama a , M. Yoshitake a , T. Chikyow a,b a Nanomaterials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan b CREST-Japan Science and Technology Corporation, Japan Received 28 February 2005; accepted 27 May 2005 Available online 10 November 2005 Abstract A composition spread metal thin film fabrication technique based on ion beam sputter deposition method was developed. The technique enables us to fabricate any desired part or a complete binary/ternary composition spread metal thin films onto a single substrate by sequentially sputtering different target materials. Composition spread metal thin films can be deposited directly on a dielectric film in patterned electrode shape for C–V and I–V measurements. The system could be especially useful in the search for new multi-component metal gate materials. # 2005 Elsevier B.V. All rights reserved. PACS: 85.40.Sz; 81.15.Cd; 81.30.Bx; 85.40.Ls; 73.40.Qv Keywords: Ion beam; Metal thin film; Composition spread; Metal gate 1. Introduction Problems such as poly-silicon (poly-Si) gate depletion, high gate resistance, and dopant penetration from heavily doped poly-Si gate become significant with the reduction of the gate length and gate dielectric thickness in complementary metal oxide semiconductor (CMOS) transistors for higher circuit integration density in semiconductor technology [1,2]. There are great interests in the replacement of the conventional poly-Si gate material with metal gate materials [3–8] because a metal gate material not only eliminates the gate depletion and dopant penetration problems but also greatly reduces the gate sheet resistance. One of the most important considerations in the selection of metal gate materials is the metal work function. A gate work function directly affects the threshold voltage of a transistor; appropriate metal gate materials with proper work functions have to be chosen for n- and www.elsevier.com/locate/apsusc Applied Surface Science 252 (2006) 2472–2476 * Corresponding author. Tel.: +81 29 851 3354x8874; fax: +81 29 860 4796. E-mail address: parhat.ahmet@nims.go.jp (P. Ahmet). 0169-4332/$ – see front matter # 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.apsusc.2005.05.078