X-ray photoelectron spectroscopy study of TiN films produced with tetrakis(dimethylamido)titanium and selected N-containing precursors on SiO2

Abstract

Low pressure chemical vapor deposition TiN films were produced on SiO2 by codosing tetrakis(dimethylamido)titanium (TDMAT) with selected N-containing precursors. The films were grown at total pressures ranging from 10−4 to 10−3 Torr and temperatures between 523 and 773 K. Film composition and chemical states were determined, without exposure to ambient pressure, using x-ray photoelectron spectroscopy (XPS). Our primary goal was to evaluate how precursor ligands affect C and N incorporation into TiN films. To this end, methylhydrazine (MH), dimethylhydrazine (DMH), and 1-aminopiperidine (AP) were chosen for their steric differences, and t-butylamine (TBA) and aniline allowed us to assess how C and N incorporation are affected by the C–N bond in the aminolike compounds versus the N–N bond in the hydrazinelike compounds. At all growth temperatures, a decrease in the carbon concentration and an increase in the N concentration were observed for the MH and DMH cases when compared to TDMAT alone, while C content increased for aniline. AP caused only a slight reduction of C at temperatures of 673 K and above. Growth temperature affected film composition and the chemical states of C, N, and Ti. At 623 K, DMH and MH reduced the C/Ti ratio from 1.0 with TDMAT alone to 0.2, while aniline increased C/Ti to 2.0 and AP and TBA had little effect. The addition of the N-containing precursors causes the XPS C 1s peak to broaden and shift to higher binding energy; the N 1s peak also broadened, suggesting that, compared to TDMAT alone, more C–N bonds are formed. Furthermore, the Ti 2p peak shifted to higher binding energy and became broader upon codosing, suggesting the incomplete conversion of Ti (IV) to Ti (III) in the TiN film. Postdosing with MH and DMH supports the conclusion that surface reactions occur between TDMAT and the hydrazinelike precursors.

Spectroscopic Evidence for Hydrogen Diffusion through a Several-Nanometers-Thick Titanium Carbonitride Layer on Silicon

“…High carbon content (from 25 to 35 at. % in these experiments, as confirmed by Auger electron spectroscopy, AES) is consistent with the previous studies. , The AES studies also confirmed the absence of silicon in the topmost layers, which suggests that the film produced is continuous. The thickness of the carbonitride layer was estimated to be ∼10 nm on the basis of the ex situ time-of-flight secondary ion mass spectrometry and atomic force microscopy (AFM) studies performed at the Surface Analysis Facility at the University of Delaware.…”

Correlation of Heating Rates, Crystal Structures, and Microwave Dielectric Properties of Li2ZnTi3O8 Ceramics

“…16 In this work, the binding energy of Ti 2p 2/3 in Li 2 ZnTi 3 O 8 ceramics heated at 1 and 3°/min was 456.50 eV and 458.30 eV, respectively. The binding energy of Ti 2p 2/3 shifted to lower energy when heated at 1 to 3°/min, which indicated that reduction for Ti 4+ to Ti 3+ had occurred, as also reported by Endle et al 17 In general, formation of oxygen vacancies readily occurs during high temperature sintering at low heating rates; this is accompanied by reduction of Ti 4+ ions to maintain equilibrium with the low oxygen activity in air. 18 The binding energy of Ti 2p 2/3 for Li 2 ZnTi 3 O 8 ceramic heated at 3°/min was 458.30 eV, in agreement with that for Ti 4+ , which confirmed that the higher heating rate restricted reduction of the Ti 4+ ion.…”

Strain Relaxation in Sol−Gel Grown Epitaxial Anatase Thin Films

“…As shown in Supporting Information 2, the binding energy of Ti 2p 3/2 from the 350 °C annealed film was 458.2 eV, lower than 458.5 eV from the 900 °C annealed one. According to Endle et al and Jiang et al, the Ti 2p 3/2 peak shifts to lower binding energy, which results from the presence of Ti 3+ ions. Since Ti 3+ ions are generated with oxygen vacancies, the lower binding energy shift supports the presence of oxygen vacancies in the 350 °C annealed film.…”