ELECTRICAL CHARACTERIZATION OF ULTRATHIN Al{sub}2O{sub}3 THIN FILMS GROWN BY ATOMIC LAYER DEPOSITION

摘要

Al{sub}2O{sub}3 is an important insulator and is a candidate to replace SiO{sub}2 as a gate dielectric in MOSFETS. Al{sub}2O{sub}3 films were deposited on a variety of substrates by atomic layer deposition (ALD) using alternating exposures of trimethylaluminum and H{sub}2O in a viscous flow reactor. The electrical properties of ALD Al{sub}2O{sub}3 films were evaluated by performing I-V and C-V measurements with a mercury probe. The electrical properties of the Al{sub}2O{sub}3 ALD films were examined versus Al{sub}2O{sub}3 thickness from 30 A to 2400A. I-V measurements revealed very low leakage currents, with resistivities up to 10{sup}16 Ωcm. Fowler-Nordheim (FN) tunneling was seen at high electric fields, and direct tunneling current was observed for films thicknesses < 45 A. We also examined the dependence of growth temperature on ALD Al{sub}2O{sub}3 electrical properties. Films were grown between 125° and 425°C. A dielectric constant k=9 was measured for thick films grown at 350°C.