Ultrathin HfO2 films grown on silicon by atomic layer deposition for advanced gate dielectrics applications

✍ Scribed by E.P. Gusev; C. Cabral Jr.; M. Copel; C. D’Emic; M. Gribelyuk

• Publisher: Elsevier Science
• Year: 2003
• Tongue: English
• Weight: 584 KB
• Volume: 69
• Category: Article
• ISSN: 0167-9317
• DOI: 10.1016/s0167-9317(03)00291-0

✦ Synopsis

We report on growth behavior, structure, thermal stability and electrical properties of ultrathin (,10 nm) hafnium oxide films deposited by atomic layer deposition using sequential exposures of HfCl and H O at 300 8C on a bare silicon surface 4 2 or a thin thermally grown SiO -based interlayer. Compared to good quality continuous films deposited on SiO surfaces, 2 2

HfO deposited on HF-last treated Si surfaces show a non-uniform, island-like morphology and poor electrical properties due 2 to poor nucleation on H-terminated Si. As-deposited films have a significant amorphous component and undergo crystallization to a monoclinic phase above |500 8C. Crystallization behavior is found to be dependent on film thickness with higher crystallization temperatures for thinner films. HfO on an ultrathin SiO interlayer shows good electrical properties 2 2 3 4

with gate leakage current reduced by a factor of 10 -10 with respect to conventional SiO gate dielectrics which justifies its 2 consideration as a candidate for high-K dielectric for future CMOS devices.