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

Electrical characteristics of α-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⁺ and Ni⁺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 α-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 α-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⁺ and from the electron localized states at the Si surface due to the insufficient sputter-cleaning by ion irradiation