Growth of yttrium oxide thin films from β‐diketonate precursor

Abstract

Yttrium oxide thin films were deposited in a flow‐type ALE reactor from Y(thd)3 (Hthd  2,2,6,6‐tetramethyl‐3,5‐heptanedione) and either ozone or oxygen. The influence of the substrate and source temperatures, pressure and pulse durations on the film growth on soda‐lime and silicon substrates was studied. Films were also grown on Corning glass, sapphire and Si/CeO2 substrates to study the effect of the substrate on the growth rate and crystallinity of the films. Spectrophotometry, XRD and AFM were used to determine the optical properties, thickness, crystallinity and surface morphology of the films. All the films deposited with ozone were crystalline, but differences in preferential orientation depending on the substrate were observed. The growth rate with ozone was about 0.8 Å cycle−1 on all substrates except sapphire where it was higher. The films deposited with oxygen were less crystalline and the growth rate was significantly lower than in depositions with ozone under the same growth conditions.

Low-Temperature ALE Deposition of Y2O3 Thin Films from β-Diketonate Precursors

“…3). The growth rates at 425 C were comparable to those observed during the previous experiments by Mölsä et al [34] Pulse times for Y(thd) 3 and ozone were studied in more detail at 350 C. At very short pulsing times, the deposition rate was found to be dependent on each of the reactant pulses ( Fig. 4).…”

“…These results are comparable to the ALE-deposited films at higher temperatures. [34] In a surface-controlled ALE process, the growth rate tends to decrease when a precursor is replaced by a larger variant, which is due to steric hindrance of the precursor molecules at the substrate surface. In the case of the Y(thd) 3 (bipy) precursor, this was not the case.…”

“…[32,33] ALE deposition of Y 2 O 3 has also been reported, using Y(thd) 3 as the precursor and deposition temperatures higher than 425 C, but the growth rates were then observed to increase with increasing temperature. [34] This indicates absence of a true ALE temperature window, which can cause difficulties when multicomponent compounds are deposited, as well as giving problems with accurate thickness control.…”

ALD of YF3 Thin Films from TiF4 and Y(thd)3 Precursors

“…The aim of the present work was to discover if YF 3 thin films can be deposited by ALD using TiF 4 as a fluorinating agent, while using Y(thd) 3 as a cation precursor. Y(thd) 3 has already been used in ALD for depositing, e.g., Y 2 O 3 , [30][31][32][33] YScO 3 , [34] and Y 2 O 2 S [35] thin films. Another aim (given that the reaction took place) was to study various film properties including the composition of the films, because the key question is how complete the reaction can be, i.e., how completely thd ligands, and especially Ti atoms, can be eliminated from the final film.…”

High Growth Rate of Erbium Oxide Thin Films in Atomic Layer Deposition from (CpMe)3Er and Water Precursors

“…[25,26] In addition, we have previously reported the ALD of erbium oxide using Er(thd) 3 (thd = 2,2,6,6-tetra-methyl-3,5-heptane-dione) and ozone as precursors. [27,28] b-Diketonate-type thd-complexes are volatile, and have frequently been utilized as precursors in ALD, [29] for example in the case of Sc 2 O 3 , [30] Y 2 O 3 , [31,32] La 2 O 3 , [33] CeO 2 , [34,35] as well as other Ln 2 O 3 films (Ln = Nd, Sm, Eu, Gd, Dy, Ho, Tm). [4,28,36] b-Diketonates do not readily react with water, but require the use of a stronger oxidizer, such as ozone, to produce oxide thin films with low carbon and hydrogen content.…”