The effect of the amide Ti precursors, tetrakis dimethyl amido titanium (TDMAT), tetrakis ethylmethyl amido titanium (TEMAT), and tetrakis diethyl amido titanium (TDEAT) on the atomic layer deposition of TiN film with ammonia was studied. Surface decomposition mechanism of each precursor was studied with in-situ Fourier transform infrared spectroscopy. It was confirmed that ethyl ligand in the precursor was more stable than methyl and the surface decomposition temperature of TDMAT, TEMAT, and TDEAT was 175, 200, and 250 °C on the SiO2 surface, respectively. The resistivity of the film was decreased with the increase in the substrate temperature due to the film crystallization. The TiN film deposited with TDMAT gave the lowest resistivity even though the atomic layer deposition temperature window was lowest due to the largest amount of carbon incorporation. It was confirmed that carbon incorporation leads to TiC formation and suppressed the postdeposition oxygen uptake possibly due to the elimination of vacancy in the film.

The interface between a dielectric thin film and a metal electrode is studied to improve reliability as well as electrical properties of the metal–insulator–metal (MIM) capacitor in dynamic random‐access memory (DRAM) devices. The interfacial layers between a dielectric thin film and a metal electrode play important functional roles such as increasing the electrical barrier or preventing oxygen defects in high‐k dielectrics. By introducing an electrical barrier layer or a sacrificial layer at the metal–dielectric interface for engineering the electronic band, lattice, or dipole, various effects could be confirmed such as the conduction band offset (CBO), bandgap or mismatch modulation for controlling the dielectric loss depending on the AC frequency or leakage current of MIM capacitors. Upon the insertion of Al2O3 as an electrical barrier layer, CBO increased because of the band engineering. Further, upon the insertion of TiO2 as a sacrificial layer at the interface, CBO increased because of the dipole formation at the interface, attributed to the difference in electronegativity. Thus, a robust MIM capacitor for DRAM that maintains a low leakage current and has improved reliability which is realized using the proper combination of interfacial layers.

H2/CH4 mixture gas was introduced as a reactive gas for plasma enhanced atomic layer deposition (PEALD) to deposit TiCxNy film as a gate electrode, and it was compared with H2 and NH3 PEALD. CH4 stimulated the formation of TiC phase and suppressed the post deposition oxygen uptake to give similarly conductive film as NH3 PEALD but with lower work function. Too high concentration of CH4 (>1.5 mol%), however, increased the free carbon impurity content, and therefore, increased the film resistivity. The resistivity of the TiCxNy film was decreased with the increase of the plasma power and substrate temperature due to the change in film composition and crystallinity. The TiCxN1-x films deposited using H2/CH4 and NH3 PEALD showed stoichiometric composition and low resistivity (<1,000 μΩ·cm). In contrast, the film deposited using H2 PEALD showed higher oxygen concentration and resistivity than other PEALD processes. The C-V curve measured with the capacitor of H2/CH4 PEALD TiCxNy film and hafnium silicate film was shifted –0.19 V away from the C-V curve of the NH3 PEALD film due to the work function difference, which was also confirmed by ultraviolet photoelectron spectroscopy (UPS).