Amorphous Si-rich tungsten silicide with a low work function near the conduction band edge of Si

The capacitance-voltage characteristics of MOS capacitors and ab initio theoretical calculations revealed that an amorphous film composed of WSin clusters (n = 6-12) had a low effective work function of 4.0 eV on SiO2 with excellent thermal stability up to 600 degrees C. In Si Schottky diodes with WSin insertion, the electron Schottky barrier height (SBH) was 0.58 eV for n = 6 and reduced to 0.45 eV when n = 12. The n-dependency of SBH was attributed to the surface passivation of WSin becoming more effective as n increased, with annealing leading to a lower value of 0.32 eV.