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

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