The study of diffusion barrier layer TiN in Cu/TiN/TiSi/sub 2//Si contact system

A comparative study of rapid thermal nitridation (RTN) of Ti, reactively-ion-sputtered (RIS), and low pressure chemical-vapor-deposited (LPCVD) TiN thin films as diffusion barriers for Cu/TiN/TiSi/sub 2//n/sup +/Si contact system has been done. The properties of TiN films were investigated by sheet resistance measurement, X-ray diffraction analysis (XRD), X-ray photoelectron spectroscopy (XPS), and Auger electron spectroscopy (AES). The thermal stability of Cu/TiN/TiSi/sub 2//n/sup +/Si contact system was studied by diode leakage current and contact resistance measurements. The leakage current measurements did not show deterioration of n/sup +/-p diode junction up to 475/spl deg/C for the RTN and LPCVD TiN diffusion barriers. The RIS TiN film was stable up to 450/spl deg/C for 30 minutes only, after which Cu started to diffuse into the n/sup +/Si substrate. The reasons for the higher thermal stability of RTN and LPCVD TiN compared to RIS TiN can be deduced from the microstructural differences in the three TiN films.