Electrical characteristics of Ni/Si and /spl alpha/-Fe/Si structures grown by low energy direct ion beam deposition

Electrical characteristics of /spl alpha/-Fe/Si and Ni/Si structures grown by mass-separated low energy direct ion beam deposition are described. Films were grown at 10 eV-200 eV by irradiating Fe/sup +/ and Ni/sup +/ion on n-type Si[111] and Si[100] substrates at room temperature without removing the native oxide layers. High-resolution TEM studies revealed that high quality interfaces could be obtained in both /spl alpha/-Fe/Si and Ni/Si structures. V-I characteristics showed the formation of Schottky junctions in the Ni/Si[111] and the Ni/Si[100] structures grown at 20 eV-200 eV. However voltage breakdowns at reverse bias were observed in the /spl alpha/-Fe/Si[111] structures grown at low ion energies of 10 eV-50 eV. These characteristics are discussed from the difference of the work function between Ni and Fe/sup +/ and from the electron localized states at the Si surface due to the insufficient sputter-cleaning by ion irradiation.