Fermi-level depinning in Mo/Si junctions by insertion of amorphous Si-rich Mo silicide film formed via gas-phase reactions of MoF6 with SiH4

Abstract

We demonstrate the reduction of the electron Schottky barrier height (SBH) to 0.48 eV at Mo/n-type Si junctions through the insertion of a semimetal Si-rich Mo silicide (MoSi n , n = 7.9) film. Raman scattering measurements elucidated the persistence of the same amorphous structure within the MoSi n film even when subjected to temperatures as high as 900 °C. This excellent thermal stability yielded a notable result: preservation of the SBH modulation effect even following annealing at 700 °C. Moreover, we investigated the capacitance−voltage characteristics of MOS capacitors, revealing that MoSi n film has a remarkably low effective work function, measuring 4.1 eV when deposited onto SiO2. The deposition of MoSi n film was accomplished with an excellent coverage by using MoF6 and SiH4 gases. Thus, MoSi n film is a promising contact material in advanced CMOS transistors.