Enhanced Thermal Stability and Reduced Specific Contact Resistivity in Titanium-Based Ohmic Contact with an Ultra-Thin Molybdenum Interlayer

This investigation reveals a practical method for improving thermal stability and reducing the specific contact resistivity (ρ
_c
) of titanium-based Ohmic contact. Inserting an ultrathin molybdenum (Mo) layer, with thicknesses ranging from 3 to 10 Å, between titanium (Ti) and heavily doped silicon (Si) substrates effectively impedes the further diffusion of Si into the metal layer. Mo silicide contributes to lowering the temperature required for the formation of the C54-phase Ti silicide by 50 °C to 100 °C and facilitates the emergence of the low-resistance phase C54-TiSi
₂
. Experimental evidence indicates that the insertion of thinner Mo layers significantly reduces ρ
_c
, which remains around the order of 10
^-8
Ω·cm
²
after extensive annealing at 750 °C for 30 minutes.