Efficiency of TiN diffusion barrier between Al and Si prepared by reactive evaporation and rapid thermal annealing

Abstract

TiN layers prepared by reactive evaporation and rapid thermal annealing were tested as diffusion barrier between Al and Si. First, Rutherford backscattering spectroscopy ͑RBS͒ analysis of Al/ Ti͑N͒/Ti/Si and Al/Ti͑N͒/Si multilayer structures showed that Si does not diffuse out up to a sintering temperature of 550°C. However, as the temperature increases beyond 450°C, Al starts to react with TiN. This reaction leaves less than half the TiN original thickness after a 30 min anneal at 550°C. The RBS results indicate that TiN, crystallized at a temperature around 850°C, forms a good barrier between Al and Si. Electrical measurements on various microelectronic devices were performed to verify this. Annealing of Ti͑N͒ at 900°C leads to a breakdown of p-MOS ͑metaloxide-semiconductor͒ devices while n-MOS devices still work properly. Annealing at 800°C gives good results on both MOS types except that the contact resistance of a p-type resistor is higher than desired. The electrical circuit failure is mainly due to dopant loss from the active area of the device into the titanium silicide which forms during the rapid thermal annealing at 800 or 900°C of the deposited Ti͑N͒ layers.

Anisotropic elasticity ofIVBtransition-metal mononitrides determined byab initiocalculations

“…In particular, their high activation energy against electromigration, coupled with superior electrical conductivity, high melting point, and excellent chemical stability has made these "refractory hard metals" extensively used for diffusion/reaction barriers in metallization schemes for semiconductor and photovoltaic technology, and desirable candidates for new materials in electronic devices. [2][3][4][5] Furthermore, the discovery of ZrN and HfN-based new layer-structured high T c superconductors, [6][7][8] as well as the recent synthesis of superconducting nitrides with a new structure ͑Zr 3 N 4 and Hf 3 N 4 ͒ 9 has attracted much attention to these materials. However, the main interest in transition metal nitrides is associated with their superior mechanical properties, partially related to electronic structure, 10 that are usually tailored by the selection of specific deposition conditions, 11,12 or modified by post-growth ion treatment.…”

Fully dense, non-faceted 111-textured high power impulse magnetron sputtering TiN films grown in the absence of substrate heating and bias

“…Titanium nitride (TiN) thin films, typically deposited by reactive dc magnetron sputtering (dcMS), are widely used as hard, wear, and corrosion resistant coatings on tools and components [1][2][3][4]; diffusion barriers in microelectronic devices [5][6][7]; corrosion and abrasion resistant layers on optical components; and biocompatible layers on medical implants [8][9][10].…”

Comparison of TiN thin films grown on SiO2 by reactive dc magnetron sputtering and high power impulse magnetron sputtering

“…Its low bulk electrical resistivity, high chemical stability and high melting point make it well suited as an adhesion layer and diffusion barrier for both aluminum and copper interconnects [1,2]. More recently TiN has been suggested as a potential gate metal in metal-oxide-semiconductor (MOS) devices with high-κ gate dielectrics [3].…”