Comparison of Thermal and Mass-Transport Properties of Bi(tmhd)3, Bi(p-tol)3, and Bi(o-tol)3 MOCVD Precursors

Abstract

Metal-organic (MO)CVD processes using three different precursors (Bi(tmhd) 3 , 3 , and Bi(o-tol) 3 ) have been investigated. Combined, thermal, and mass spectroscopic investigations have provided information on their thermal robustness during sublimation processes. In-situ Fourier-transform infrared (FTIR) measurements have allowed the monitoring of masstransported precursors during MOCVD experiments. Temperature windows of 190±277 C, 170±270 C, and 150±220 C have proved suitable for the efficient vaporization of Bi(tmhd) 3 , Bi(p-tol) 3 , and Bi(o-tol) 3 , respectively, even though aryl precursors have proved to be more stable than b-diketonate during the sublimation and transport processes.Above 350 C, decomposition during the MOCVD processes has been observed for all the precursors. In the case of Bi(tmhd) 3 and Bi(o-tol) 3 it involves the ligand fragmentation, while for Bi(p-tol) 3 , dissociation of the intact aryl ring seems to occur.

MOCVD of crystalline Bi2O3 thin films using a single-source bismuth alkoxide precursor and their use in photodegradation of water

“…13 Similarly [Bi(o-tol) 3 ] and [Bi(ptol) 3 ] have been shown to be useful bismuth precursors for growth of bismuth oxide films. 14 However, the high thermal stability of these precursors requires high deposition temperatures and carbon contamination can be problematic. Trimethylbismuth has been shown to deposit α-Bi 2 O 3 films in a dual source reaction with oxygen, 15,16 however trimethylbismuth is pyrophoric and requires cooling prior to and during deposition.…”

Synthesis of multifunctional multiferroic materials from metalorganics

“…While the ortho derivative dissociates via a breakdown of the aromatic rings, in case of the para derivative the breakdown involves dissociation of the aromatic ring-methyl bond. Thermogravimetric analysis curve for Bi(thd) 3 reveals two mass losses in the ranges 80-190 • C and 190-310 • C [44]. The final residue was reported to be 2.29%.…”

“…In case of rare-earth ␤-diketonates, the volatility increases in the series from La to Lu which has been attributed to the lanthanide contraction [43]. For Bi, aryl sources, particularly triphenyl bismuth, have been equally popular because of their good thermal stability upon sublimation and during storage [44]. In case of iron precursors, metallocenes have been the other major choice apart from the ␤-diketonates.…”

“…The vaporization occurs in the range 160-280 • C with a final residue of about 5% at 350 • C. Bi(o-tol) 3 and Bi(p-tol) 3 which belong to the same class as Bi(Ph) 3 also show similar thermal characteristics. Based on the reported TG analysis Bi(o-tol) 3 and Bi(p-tol) 3 undergo single step clean evaporation in the range 170-350 • C and 170-300 • C, respectively [44]. The final residue left at 600 • C was 3.3 % and 1.4 %, respectively.…”

Synthesis and Materials Chemistry of Bismuth Tris-(di-i-propylcarbamate): Deposition of Photoactive Bi2O3 Thin Films

“…(ferroelectric perovskites) 9, 10 and Bi 2 Sr 2 CaCu 2 O 8 (high temperature superconductor). 11 Existing CVD precursors for bismuth oxides include BI 3 , [12][13][14][15][16][17][18] Bi(NO 3 ) 3, 19 BiPh 3 20- 22 and related bismuth aryls 23 and alkyls, 24 β-diketonates such as Bi(thd) 3 (thd = tetramethylheptane-dione), 23,25,26 and both simple and functionalised alkoxides, [27][28][29] all summarised in refs. 5 and 28.…”