Atomic Layer Deposition Growth of BaB₂O₄ Thin Films from an Exceptionally Thermally Stable Tris(pyrazolyl)borate-Based Precursor

The Atomic Layer Deposition of SrB2O4 Films Using the Thermally Stable Precursor Bis(tris(pyrazolyl)borate)strontium

“…In the deposition of BaB 2 O 4 and CaB 2 O 4 films, we proposed that the precise 2:1 boron/metal ratios in the films were derived from the 2:1 boron/metal ratios in the precursors. [39,40] In the present work, the boron/strontium ratios are also 2:1 within the experimental error of ERDA at growth temperatures of < 350 8C. Our ALD results can be compared with the CVD growth of metal borate films reported by Malandrino et al [41,42] CVD growth using films from MgTp 2 and oxygen at 750 8C afforded a 1:1 boron/ magnesium ratio in the film that was significantly different than the 2:1 ratio in MgTp 2 .…”

“…There are few examples in the literature of ALD precursors that deliver two elements simultaneously. [39,40,[46][47][48][49] The ALD growth of SrTa 2 O 6 films was carried out using alkoxide-based precursors having 2:1 strontium/tantalum ratios, [46,47] however the strontium/tantalum ratios in the films varied from 0.5 to 1.5, and it was suggested that volatile tantalum species were lost from the growing film. The liquid injection ALD growth of PrAlO x and NdAlO x films was performed using 1:1 neodymium/aluminum and praseodymium/aluminum isopropoxide-based precursors with water as the oxygen source.…”

Unusual stoichiometry control in the atomic layer deposition of manganese borate films from manganese bis(tris(pyrazolyl)borate) and ozone

“…The present work documents the ALD growth of films with the approximate stoichiometries Mn 3 (BO 3 ) 2 and [29][30][31] Replication of the 2:1 boron to cobalt ratio of 2 in the CoB 2 O 4 films implies that 2 physisorbs in a molecular fashion to the surface of the growing film, and is then efficiently transformed by ozone to CoB 2 O 4 . In contrast, 1 and ozone afford films of the approximate composition Mn 3 (BO 3 ) 2 , with an approximate 3:2 manganese to boron stoichiometry.…”

“…25 Film growth was achieved between 640 and 840 C, but a 1:2.5 barium to boron precursor stoichiometry was required to obtain BaB 2 26 We previously reported the atomic layer deposition (ALD) of MB 2 O 4 films (M ¼ Ca, Sr, Ba) between 250 and 400 C using CaTp 2 , SrTp 2 , and Ba(TpEt 2 ) 2 as the metal and boron precursors with water as the oxygen source. [29][30][31] Significantly, the 2:1 boron to metal ratio in the precursors was retained in the MB 2 O 4 films. ALD uniquely enables the stoichiometry control, since the depositions are conducted below the thermal decomposition temperatures of CaTp 2 , SrTp 2 , and Ba(TpEt 2 ) 2 [<400 C (Ref.…”

“…28)]. The intermediate physisorbed precursor monolayers replicate the 2:1 boron to metal precursor stoichiometry in the thin films upon treatment with the water coreactant, and the MB 2 O 4 layers are stable to B 2 O 3 loss at <400 C. [29][30][31] ALD affords conformal coverage of nanoscale features and enables subnanometer control of film thicknesses because of the self-limited growth mechanism. 32,33 ALD can also provide conformal coatings on many nanoscale materials.…”