We systematically investigated the effects of Y doping in HfO 2 dielectric layer, focusing on structural phase transformation and the dielectric properties of the resultant films. Y doping was carried out using atomic layer deposition (ALD) with a novel Y(iPrCp)2(N-iPr-amd) precursor, which exhibits good thermal stability without any decomposition and clean evaporation. As a result, the ALD process of the Y 2 O 3 films showed well-saturated and linear growth characteristics of ∼0.45 Å/cycle without significant incubation delays and produced pure Y 2 O 3 films. Then, yttrium-doped HfO 2 films with various Y/(Y + Hf) compositions (yttrium content: 0.6- 4.8 mol%) were prepared by alternating Y 2 O 3 and HfO 2 growth cycles. Structural and electrical characterization revealed that the addition of yttrium to HfO 2 induced phase transformations from the monoclinic to the cubic or tetragonal phases, even at low post-annealing temperatures of 600 C, and improved leakage current densities by inducing oxygen vacancy-related complex defects. A maximum relative dielectric constant of ∼33.4 was obtained for films with a yttrium content of ∼1.2 mol%. Excellent EOT scalability was observed down to ∼1 nm without dielectric constant degradation.
Bibliographical noteFunding Information:
This work was supported by the Industrial Strategic Technology Development Program (1004192610041926, Development of high density plasma technologies for thin film deposition of nanoscale semiconductors and flexible display processing) funded by the Ministry of Knowledge Economy (MKE, Korea), and supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST) (2011-0028594).
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Physics and Astronomy(all)
- Surfaces and Interfaces
- Surfaces, Coatings and Films