Low-temperature growth of high-k thin films by ultraviolet-assisted pulsedlaser deposition

Medium- and high-k dielectric films were grown directly on Si by ultraviole t-assisted pulsed laser deposition (UVPLD). It has been found that at the i nterface between the dielectric and Si, SiO2 layers of various thickness we re always formed. The source for this interfacial layer formation could be the physisorbed oxygen trapped inside the growing dielectric layer during t he ablation process. When trying to reduce the thickness of this low-k SiO2 layer, a marked decrease in the electrical properties was noticed. The die lectric constant of 50 nm thick barium strontium titanate (BST) thin films deposited at 600 degreesC was around 180 while the leakage current density was below 1 x 10(-5) A/cm(2) at +1.0 V. (C) 2000 Published by Elsevier Scie nce B.V.