Improvement of contact resistivity of titanium silicide on P-doped epitaxial Si using a Se interlayer

Abstract

We propose a method to reduce the contact resistivity of titanium silicide (TiSi2) on phosphorus-doped epitaxial silicon by introducing a thin Se layer at the Ti/Si interface. The Se interlayer delays transition from the C49 to the C54 phase and changes the dominant diffusing species of TiSi2 formation from Si to Ti. In addition, the Se interlayer worsens the interface roughness between TiSi2/Si. The contact resistivity of the sample with the Se interlayer improves by one order of magnitude, which is significant. This improvement is attributed to the suppressed diffusion of P and low Schottky barrier height.

Low contact resistivity of Ti/TiN/Al for NiSi2 on epitaxial Si:P structure at full low-temperature process below 450 °C

“…These methods have extremely high requirements for the thickness and uniformity controllability of the insertion layer. On the other hand, dopant segregation [3,4], the introduction of advanced annealing tools [5][6][7][8], a dopant interlayer [9], metal-induced activation [10,11] and metal silicide-induced activation [12][13][14] have been extensively studied to improve the activation concentration of impurities at the metal/semiconductor interface. In situ phosphorus-doped silcon using chemical vapor deposition techniques, which exceeds the solid solubility level, has been applied 2 × 10 21 cm 3 [15,16].…”