Silicide formation in Ni-Si Schottky barrier diodes

Abstract

Rutherford backscattering of energetic ⁴He⁺ ions has been used to study the composition and depth profile of silicide layers formed when thin nickel films evaporated on (111) and (100) silicon surfaces are heated in a nitrogen-hydrogen ambient. In the temperature range 297 to 430 degrees C two phases are seen to form sequentially. The growth of the first phase, Ni₂Si, is parabolic with time, whilst the second, NiSi, grows linearly with time. The simultaneous presence of both diffusion and reaction-rate-limiting mechanisms is implied by the parabolic and linear growth laws. An investigation of the electrical characteristics of diodes which were metallized and heat-treated simultaneously shows little change in the barrier height.