The Influence of Impurities on Cobalt Silicide Formation

Abstract

Cobalt silicide formation has been studied using thin films of Co on Si wafers with different impurity contents in the metal and with thin or thick native oxide at the Co/Si interface. The incorporation of impurities into the film was controlled by changes of the pressure during Co deposition. Two RTP systems with two different annealing ambients and heat sources were used for silicidation. For Co films with low contaminant level, thin or thick native oxide can be dissolved and good quality CoSi2 is formed. For Co films with high impurity level in the presence of thick native oxide, the silicidation can be performed, delayed, or even inhibited, depending on film thickness and annealing conditions.

Monitoring and purging dynamics of trace gaseous impurity in atmospheric pressure rapid thermal process

“…The residual gaseous impurities in these equipment are becoming an important factor in device failure thereby threatening production yield in the submicron ultralarge scale integrated industry. [8][9][10] The most common process gas used for silicidation processes is pure nitrogen or argon. Ambient cleanliness during rapid thermal annealing is becoming significantly important.…”

Towards Contact Resistance Minimization through CoSi2Formation Process Optimization on P-Doped Poly-Si by Hot Wall-Based Rapid Thermal Annealing

“…9,12,13 Tungsten silicide, titanium silicide, cobalt silicide and nickel silicide formation studies on various Si phases and structures, including silicon-on-insulator (SOI) wafers, have been reported for several decades. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] Sometimes, ion implantation on silicide layers is done to reduce line width dependence thus potentially extending the lifecycle of the selected silicide for the next generation devices with narrower line widths. 2,3,14 While various combinations (species, energy and dose) of dopant implantation for contact resistance reduction have been actively investigated, very little in the way of dopant profile modification efforts have been reported on forming silicides at the Si interface to reduce contact resistance.…”

CoSi 2 formation in the presence of interfacial silicon oxide

“…This solubility limit is dependent on the thickness of the deposited Co layer, and of its purity. 7 Once this limit is reached, there are two possibilities, depending on the initial for the ͗400͘ and ͗220͘ CoSi 2 diffraction peaks of the Ti/Co ͑10 nm͒/SiO x /Si system. The ͗400͘ peak was measured using /2 geometry, while the ͗220͘ peak was measured using grazing incidence ͑ϭ1°͒.…”