Growth and phase stabilization of HfO2 thin films by ALD using novel precursors
| Autor: | Jaakko Niinistö, Kaupo Kukli, Mikko Ritala, Leila Costelle, Markku Leskelä, Miia Mäntymäki, Esa Puukilainen |
|---|---|
| Rok vydání: | 2010 |
| Předmět: |
010302 applied physics
Chemistry Thermal decomposition Analytical chemistry chemistry.chemical_element Mineralogy 02 engineering and technology Yttrium 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Inorganic Chemistry Tetragonal crystal system Atomic layer deposition 0103 physical sciences Materials Chemistry Thermal stability Thin film 0210 nano-technology Tin Monoclinic crystal system |
| Zdroj: | Journal of Crystal Growth. 312:245-249 |
| ISSN: | 0022-0248 |
| DOI: | 10.1016/j.jcrysgro.2009.10.028 |
| Popis: | HfO 2 thin films were grown at temperatures between 250 and 400 °C by atomic layer deposition using novel cyclopentadienyl–alkylamido precursors, namely CpHf(NMe 2 ) 3 and (CpMe)Hf(NMe 2 ) 3 (Cp, cyclopentadienyl=C 5 H 5 ). Ozone was used as the oxygen source. The self-limiting growth mode was verified at 300 °C with a growth rate of 0.7–0.8 A/cycle, depending on the precursor. Thermal decomposition started to have an effect on the growth mechanism at temperatures near 350 °C. As compared to the widely applied Hf(NEtMe) 4 precursor, these novel precursors with higher thermal stability resulted in HfO 2 films with lower impurity contents. The carbon and hydrogen contents below 0.5 and 1.0 at.%, respectively, were characterized for films deposited at 300 °C from both novel precursors. The 50-nm-thick HfO 2 films deposited at 300 °C or above were crystallized in mixture of monoclinic and cubic or tetragonal phases. Doping with low amounts of yttrium and subsequent annealing of 7-nm-thick film on TiN stabilized the preferred high-permittivity cubic or tetragonal phases, resulting in low capacitance equivalent thickness and leakage current density. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect