• PDF / 215,880 Bytes
• 6 Pages / 612 x 792 pts (letter) Page_size
• 96 Downloads / 238 Views

DOWNLOAD

REPORT

---

Shiro Hino and Makoto Nakayama Precision and Intelligence Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan

Naoki Ohashi National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan

Takanori Kiguchi Center for Advanced Materials Analysis, Tokyo Institute of Technology 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8552, Japan

Eisuke Tokumitsu Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan; and Precision and Intelligence Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan (Received 26 June 2003; accepted 31 October 2003)

Hafnium oxide films were deposited on silicon substrates at deposition temperatures ranging from 190 to 500 °C by metalorganic chemical vapor deposition using an amide precursor, Hf[N(C2H5)2]4, and O2 as source materials. The effect of deposition temperature on the deposition characteristics and electrical properties of the resultant films were investigated. Reaction-limited deposition of hafnium oxide films occurred at deposition temperatures under 380 °C. Concentration of residues, such as carbon, nitrogen, and hydrogen, monotonously decreased with increasing deposition temperature, with nitrogen being the most thermally susceptible. However, surface roughness reached a minimum value at 400 °C. Amorphous films were obtained for deposition temperatures up to 450 °C, but obviously became crystallized at 500 °C. Accumulation capacitance increased with increasing deposition temperature but saturated above 400 °C. Moreover, postdeposition annealing at 800 °C caused no obvious degradation in the electrical properties of the film deposited at 400 °C.

I. INTRODUCTION

A fundamental limit to scaling of the gate dielectric of complementary metal–oxide semiconductor devices is undoubtedly approaching because decreasing the gate dielectric thickness leads to an exponential increase in leakage current from direct tunneling.1,2 To continue scaling without increasing the undesirable leakage current, high dielectric constant materials such as oxides of hafnium, zirconium, lanthanum, aluminum, and so forth, have been investigated as possible replacements for the SiO2 gate insulator.3–9 Among these metal oxides,

a)

Address all correspondence to this author. e-mail: [email protected]

584

http://journals.cambridge.org

J. Mater. Res., Vol. 19, No. 2, Feb 2004 Downloaded: 14 Mar 2015

hafnium oxide has attracted considerable attention because of its relatively high dielectric constant,10,11 wide band gap (∼5.68 eV),12,13 thermodynamic stability up to 1000 K,14,15 and compatibility with n+ poly-silicon as a gate electrode material.16 Hafnium oxide films have been deposited by metalorganic chemical vapor deposition (MOCVD),3,17 atomic layer deposition, 4,18 and sputter deposition. 16,19 MOCVD is an attractive technique because of its potential for large area growth, good composition control and fil