MOCVD of Lanthanum Oxides from La(tmhd)₃ and La(tmod)₃ Precursors: A Thermal and Kinetic Investigation

Abstract

Metal-organic (MO)CVD processes using two different precursors, (La(tmhd) 3 and La(tmod) 3 ), have been investigated. Insitu Fourier transform infrared (FTIR) spectroscopy investigations and thermal analysis have provided information on their thermal robustness during the sublimation processes and mass-transport properties during MOCVD experiments. Both precursors can be efficiently vaporized in the temperature range 160-230°C even though La(tmod) 3 exhibits higher volatility. Lanthanum oxides have been efficiently deposited using a direct liquid injection (DLI) equipped MOCVD reactor in the temperature range 350-500°C for both precursors. The effect of the addition of tetraglyme to the precursor solution has been evaluated. Films mainly consist of different phases of La 2 O 3 and LaO(OH), while the carbon-containing La 2 O 2 CO 3 phase was observed only on the surface, with no relevant carbon contamination being present in the bulk of the film.

O 3 -based atomic layer deposition of hexagonal La2O3 films on Si(100) and Ge(100) substrates

“…La 2 O 3 films have been grown on Si substrates by various techniques, namely, molecular beam deposition, 32,33 sputtering, 11,34 metal organic chemical vapor deposition, 35,36 and electron beam evaporation. 37,38 Conversely, the spread regarding the methods for La 2 O 3 deposition on Ge substrates is narrower since the majority of published work is predominantly concerned with La 2 O 3 growth by electron beam evaporation 20,21 and molecular beam deposition.…”

Potential of La-Doped SrTiO3 Thin Films Grown by Metal–Organic Vapor Phase Epitaxy for Thermoelectric Applications

“…La-doped SrTiO 3 thin films with a thickness between 30 and 50 nm were grown via liquid-delivery spin MOVPE in an oxygen-argon atmosphere at a chamber pressure of 15 mbar. The metal–organic (MO) compounds Sr­(tmhd) 2 -tetraglyme, Ti­(O i P r ) 2 (tmhd) 2 , and La­(tmhd) 3 were solved in dry toluene (<2 to 3 ppm H 2 O) and used as precursors. The deposition method requires evaporating the liquid MO precursors in a flash evaporator.…”

“…For all three precursors, a steep drop is observed at elevated temperatures, which indicates the onset of pyrolysis related to the splitting off (detachment) of the different ligands. 27,29,40 However, the kinks occur at different temperatures, which increases in the sequence Sr(tmhd) 2 -tetraglyme − Ti-(O i P r ) 2 (tmhd) 2 − La(tmhd) 3 . Furthermore, while for the La und Ti precursors only two temperature ranges with different slopes can be identified, the TG curve of the Sr precursor obviously exhibits three temperature ranges.…”

Atomic Layer Deposition of La2O3 Film with Precursor La(thd)3-DMEA

“…As shown in Figure 4, complex 2 exhibited a sufficiently high vapor pressure at a low temperature of 130 • C under atmospheric pressure. Specifically, it existed as a liquid with a vapor pressure of approximately 0.1 Torr [40]. Additionally, thermogravimetric analysis (TG) on complex 2 was performed to confirm that it could be maintained at a suitable evaporation temperature during its transfer from the evaporation reactor to the deposition reactor without undergoing thermal decomposition.…”