| Autor: |
Triyoso, Dina H., Hegde, Rama I., White Jr., Bruce E., Tobin, Philip J. |
| Předmět: |
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| Zdroj: |
Journal of Applied Physics; 6/15/2005, Vol. 97 Issue 12, p124107, 9p, 2 Black and White Photographs, 1 Diagram, 1 Chart, 12 Graphs |
| Abstrakt: |
Physical and electrical characteristics of atomic-layer-deposited HfO2 deposited using hafnium tetrachloride (HfCl4) and tetrakis[ethylmethylaminohafnium] (TEMAHf) precursors were investigated. The oxidant used for the solid HfCl4 is water, while ozone (O3) is used to oxidize the liquid TEMAHf. Physical properties of these dielectric films were studied by ellipsometry, atomic force microscopy, x-ray diffraction (XRD), secondary-ion-mass spectrometry (SIMS), and transmission electron microscopy. A linear growth rate is observed for the HfO2 deposited using both types of precursors. The HfO2 deposited using TEMAHf has a growth rate of ∼0.8 Å/cycle compared to ∼0.5 Å/cycle for HfO2 deposited using HfCl4. The early growth characteristics of these films as studied by time-of-flight SIMS were found to be similar. The HfO2 deposited by HfCl4 is smoother and denser than HfO2 deposited by TEMAHf. Higher-temperature anneals resulted in significant changes in surface morphology and an increase in roughness of the dielectric films. XRD analysis revealed that after 900 °C annealing, both HfO2 films become monoclinic with differences in preferred orientation. Both types of precursors yielded HfO2 transistors with comparable electrical characteristics. However, the peak transconductance (Gm) degradation for the TEMAHf–HfO2 devices is significantly larger compared to that produced with HfCl4–HfO2. The dielectric constant (k) value for HfCl4–HfO2 films is higher compared to that of the TEMAHf–HfO2 films. The possible reasons for the peak Gm degradation of the TEMAHf–HfO2 films and the observed higher k values for the HfCl4–HfO2 films are discussed in the paper. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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