In situ spectroscopic ellipsometry study on the growth of ultrathin TiN films by plasma-assisted atomic layer deposition

The growth of ultrathin TiN films by plasma-assisted at. layer deposition (PA-ALD) was studied by in situ spectroscopic ellipsometry (SE). In between the growth cycles consisting of TiCl4 precursor dosing and H2-N2 plasma exposure, ellipsometry data were acquired in the photon energy range of 0.75-5.0 eV. The dielec. function of the TiN films was modeled by a Drude-Lorentz oscillator parametrization, and the film thickness and the TiN material properties, such as conduction electron d., electron mean free path, elec. resistivity, and mass d., were detd. Ex situ anal. was used to validate the results obtained by in situ SE. From the in situ spectroscopic ellipsometry data several aspects related to thin film growth by ALD were addressed. A decrease in film resistivity with deposition temp. between 100 and 400 DegC was attributed to the increase in electron mean free path due to a lower level of impurities incorporated into the films at higher temps. A change in resistivity and electron mean free path was obsd. as a function of film thickness (2-65 nm) and was related to an increase in electron-sidewall scattering for decreasing film thickness. The TiN film nucleation was studied on thermal oxide covered c-Si substrates. A difference in nucleation delay was obsd. on these substrates and was related to the varying surface hydroxyl d. For PA-ALD on H-terminated c-Si substrates, the formation of an interfacial SiNx film was obsd., which facilitated the TiN film nucleation. [on SciFinder (R)]