Tungsten/titanium nitride low-resistance interconnections durable for high-temperature processing

Abstract
Newly developed W/TiN bilayer interconnections, able to withstand high-temperature processing after metalization, are described. Minimum TiN thickness was found to be 100 Å in order to retain adhesion between W and SiO2, while being a reaction barrier between W and Si. Silicidation rate in the W/TiN/Si system was reduced by about 4.5 orders of magnitude, in comparison with a W/Si system at 950 °C. TiN/p+-Si contact resistivity on the order of 10−6 Ω cm2 was realized by boron ion implantation through a TiN layer and rapid thermal annealing for boron activation at temperatures above 1000 °C.