Atomic layer deposition of hafnium dioxide thin films from hafnium tetrakis(dimethylamide) and water

• Published in: Thin solid films 2005-11, Vol.491 (1), p.328-338
• Main Authors: Kukli, Kaupo, Pilvi, Tero, Ritala, Mikko, Sajavaara, Timo, Lu, Jun, Leskelä, Markku
• Format: Article
• Language: English
• Subjects: Atomic layer deposition; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Dielectric properties of solids and liquids; Dielectrics; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport in interface structures; Exact sciences and technology; Hafnium dioxide; Materials science; Metal-insulator-semiconductor structures (including semiconductor-to-insulator); Methods of deposition of films and coatings; film growth and epitaxy; Permittivity (dielectric function); Physics; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties)
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2005.05.050

HfO 2 films were grown by atomic layer deposition from Hf[N(CH 3) 2] 4 and H 2O on Si(100) substrates in the temperature range of 205–400 °C. Around 250 °C, nearly amorphous but dense films grew without marked dependence of their physical properties on the process parameters, such as Hf[N(CH 3) 2] 4 pulse length. Incomplete reaction between adsorbed alkylamide species and water at the lowest temperatures, and thermal decomposition of the precursor at the highest temperatures were the likely reasons to increased impurity content and deterioration the film properties. At intermediate temperatures, films with permittivity of 15–16 and breakdown fields 4–5 MV/cm could be grown. The residual hydrogen, carbon and nitrogen contents in the as-deposited films were marked, exceeding several at.%. Hydrogen content was reduced 4–5 times by annealing procedures.