Electrical and structural characterization of PLD grown CeO2–HfO2 laminated high-k gate dielectrics

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Karakaya, K. and Barcones, B. and Rittersma, Z.M. and Berkum van, J.G.M. and Verheijen, M.A. and Rijnders, G. and Blank, D.H.A. (2006) Electrical and structural characterization of PLD grown CeO2–HfO2 laminated high-k gate dielectrics. Materials Science in Semiconductor Processing, 9 (6). pp. 1061-1064. ISSN 1369-8001

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Abstract:The electrical and physical properties of CeO2–HfO2 nanolaminates deposited by pulsed laser deposition (PLD) are
investigated. The properties of the nanolaminates are compared with binary CeO2 and HfO2 thin films. Layers were
deposited using CeO2 and HfO2 targets at substrate temperatures between 220 and 620 1C in 10 Pa Ar+H2 or O2. In situ
post deposition anneal (PDA) was achieved by controlled cooling down to room temperature with pO2 ¼ 10 kPa.
Nanolaminates starting with CeO2 show lower EOT and leakage compared to layers starting with HfO2. TEM and XRD
analyses showed thickness-dependent crystallinity of the layers, varying from amorphous to highly oriented polycrystalline
phase. C–V and I–V measurements were done on the capacitors. Lowest fixed-charge density Qf ¼ 4 1012 cm2 was found
for the nanolaminates deposited at 520 1C. The k values of the nanolaminates extracted by the EOT-physical thickness
plots were found to be 141, 48 and 22, for deposition temperatures 420, 520 and 620 1C, respectively. Higher k value for
lower deposition temperatures is explained by the thickness dependent morphology of the layers. An EOT ¼ 0:95nm with
Jg ¼ 1:1 102 A=cm2 was found for binary HfO2 layer with 4 nm physical thickness. Lowest leakage current density
Jg ¼ 1:9 107 A=cm2 was for a 4nm laminate deposited at 420 1C and with a cooling rate of 2 1C/min during PDA
Item Type:Article
Copyright:© 2006 Elsevier
Faculty:
Science and Technology (TNW)
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Link to this item:http://purl.utwente.nl/publications/59229
Official URL:http://dx.doi.org/10.1016/j.mssp.2006.10.024
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