Abnormal junction leakage characteristics in titanium-capped cobalt disilicide were investigated. The cobalt silicide n+-p junctions, fabricated with different capping layers, were characterized by current–voltage measurements and transmission electron microscopy. The reverse junction leakage currents of Ti-capped 13.5-nm-thick cobalt disilicide (CT) are higher than those of TiN-capped samples. The activation energy of CT at temperatures below 80 °C is 0.41 eV, and its dominant leakage mechanism is consistent with phonon-assisted tunneling. Transmission electron microscopy analysis indicates the existence of island phases and precipitates located at the silicide/Si interface, which are titanium disilicide and CoxTi1−xSi2 phases, as evidenced by energy dispersive spectroscopy. As a result, for the case of CT, the reasons for higher junction leakage currents and their field dependence appear to be the result of the diffusion of Ti atoms into CoSi2 grain boundaries and the resulting formation of TiSi2 and CoxTi1−xSi2 phases, which gives rise to a rougher silicide interface and a close spacing between silicide and the junction.

Articles you may be interested inStrain induced changes in the gate leakage current of n-channel metal-oxide-semiconductor field-effect transistors

The interface trap properties of metal/oxide/silicon field-effect transistors with high-k gate dielectrics are evaluated by the charge pumping method and related with electrical characteristics of the transistors. It is found that the gate leakage current is very sensitive to the interface traps by which the barrier height of Fowler–Nordheim tunneling is also influenced. The inversion layer mobility is greatly influenced by the charges in the gate insulator as well as by the interface traps. We propose a simple method to extract the geometrical mean value of capture cross sections of traps ranging from 7.03×10−21 to 2.22×10−22 cm2.

This letter will present the effects of nitrogen implantation on shallow p+-n junction formation in silicon. The p+-n junctions fabricated at different implantation conditions and heat budgets were characterized by secondary ion mass spectroscopy, current–voltage and capacitance–voltage measurements, and analyzed by transport of ions in matter simulation. The capacitance–voltage measurements of nitrogen implanted samples revealed the one-sided abrupt junction properties, and the current–voltage measurements indicated the shallow junction characteristics due to boron diffusion suppression by nitrogen. The activation energy is about 0.39 eV for temperatures below 80 °C, and its dominant leakage mechanism is phonon-assisted tunneling. At a reverse bias of −3 V, the leakage current density was 5.217×10−8 A/cm2 at −3 V, which is comparable to that of a conventional p+-n junction.

No abstract