Chemical interaction between atomic-layer-deposited HfO2 thin films and the Si substrate

• Published in: Applied physics letters Vol. 81; no. 2; pp. 334 - 336
• Main Authors: Cho, Moonju, Park, Jaehoo, Park, Hong Bae, Hwang, Cheol Seong, Jeong, Jaehack, Hyun, Kwang Soo
• Format: Journal Article
• Language: English
• Published: 08-07-2002
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.1492320

HfO 2 thin films were deposited on Si wafers using an atomic layer deposition technique at temperatures ranging from 200 to 400 °C with HfCl4 as the precursor and H2O as the oxidant. The time-dependent interfacial-layer growth behavior was dependent on the deposition temperature. The interfacial layer grew with increasing deposition time at 200 °C. However, the film thicknesses decreased with increasing deposition time after reaching a certain maximum value at 300 and 400 °C due to the enhanced dissolution of SiOx into the growing films at these temperatures. Post-annealing at 800 °C under a N2 atmosphere resulted in the precipitation of a Si-rich interfacial layer even for the initially interfacial layer free films. This had the effect of reducing the capacitance density of the films.