Electrical characterization of Al2O3 on Si from thermally oxidized AlAs and Al

Abstract

The scaling limit for VLSI gate oxide (SiO2) is 15-20 Angstrom that is determined by the large direct-tunneling leakage current. Further scaling to improve device performance can be obtained using a higher dielectric constant material. We have studied the Al2O3 to use as an alternative gate dielectric. To ensure good quality, Al2O3 is thermally oxidized from MBE-grown AlAs or Al on Si-substrates. Experimental results indicate that the leakage current from oxidized AlAs is larger than that from directly oxidized Al, which may be due to the weak As2O3 inside Al2O3. The leakage current of a 53 Angstrom Al2O3 is already lower than that of SiO2 with an equivalent oxide thickness of 21 Angstrom. (C) 1999 Published by Elsevier Science B.V. All rights reserved.