Effects of Low Temperature O2 Treatment on the Electrical Characteristics of Amorphous LaAlO3 Films by Atomic Layer Deposition
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CitationLiu, Yiqun, Hoon Kim, Jun-Jieh Wang, Huazhi Li, and Roy G. Gordon. 2008. Effects of low temperature O2 treatment on the electrical characteristics of amorphous LaAlO3 films by atomic layer deposition. Physics and Technology of High-k Gate Dielectrics. Special Issue, ECS Transactions 16, no. 5: 471-478.
AbstractAmorphous LaAlO3 films were deposited on hydrogen-terminated silicon substrates by atomic layer deposition (ALD) at 300 oC. The precursors were lanthanum tris(N,N'-diisopropylformamidinate), trimethylaluminum (TMA) and water. Capacitance-voltage measurements made on ALD MoN/LaAlO3/Si stacks showed humps especially at low frequencies. They were effectively removed by O2 treatment at 300 o C without affecting the dielectric constant (kappa~15). The O2 treatment can be carried out either after deposition of a LaAlO3 film, or after each ALD cycle. The O2 treatment also lowered the leakage current from 80 mA cm-2 to 1 mA cm-2 for EOT = 1.3 nm. This indicates that oxygen vacancies are the main defects in as-deposited LaAlO3. Oxygen treated LaAlO3 is one of the best candidates for future high-kappa dielectric material due to its low leakage, low defect density and abrupt interface with silicon.
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