Expedient route to volatile zirconium metal-organic chemical vapor deposition precursors using amide synthons and implementation in yttria-stabilized zirconia film growth

Abstract

This communication reports rapid, efficient syntheses of the zirconium-organic metal-organic chemical vapor deposition (MOCVD) precursors Zr(acac)4 and Zr(dpm)4 (acac = acetylacetonate; dpm = dipivaloylmethanate) as well as a new, highly volatile, air- and moisture-stable Zr precursor based on a tetradentate Schiff-base ligand, Zr(tfacen)2 (tfacen = bis-trifluoroacetylacetone-ethylenediiminate). The improved one-step synthetic routes employ tetrakis(dimethylamido)zirconium as a common intermediate and represent a major advance over previous methods employing ZrCl4 or diketonate metathesis. Furthermore, Zr(tfacen)2 is shown to be an effective metal-organic precursor for the MOCVD-mediated growth of (100) oriented yttria-stabilized zirconia thin films.

Nanocrystalline ZrO2thin films on silicon fabricated by pulsed-pressure metalorganic chemical vapor deposition (PP-MOCVD)

“…Zirconia films grown by other CVD techniques at comparable temperatures have a nanocrystalline grain size that is similar, 28,29 although most films exhibit a mixture of monoclinic and tetragonal phases with some indication of preferred orientation. One paper reported the growth of extremely large zirconia grains of 5 to 8 m using MOCVD, 30 but upon examination of the SEM data presented, the columns of zirconia appear to be on the order of 100 nm in width.…”

New sterically hindered Hf, Zr and Y β-diketonates as MOCVD precursors for oxide films

“…Scaling down complementary metal-oxide-semiconductor (CMOS) devices is limited by increased current leakage for sub-0.1 mm SiO 2 gate dielectric films resulting in unacceptable power consumption and decreased reliability. [1][2][3] ZrO 2 and especially more temperature stable 4 HfO 2 are among the most promising candidates to replace SiO 2 in microelectronics due to their high dielectric constants (20)(21)(22)(23)(24)(25) and reasonable band alignment to silicon. 1 Thermodynamic calculations predict their high chemical stability in contact with Si, 5 but formation of interfacial SiO 2 layers was observed for these oxides.…”

“…[1][2][3]9,14,15 MOCVD has a number of advantages over physical methods, such as the possibility to grow uniform layers on large area substrates, even non-planar ones, the possibility of bulk production and easy composition control in complex oxide films, especially in the case of liquid injection MOCVD. 1 The metal organic precursors used for CVD of HfO 2 , ZrO 2 and YSZ are 1,2 (M ~Zr, Hf): amides M(NEt 2 ) 4 ; 15,16 alkoxides M(OR) 4 [OR ~OBu t ; 3,9b,17 mmp (1-methoxy-2-methyl-2propanolate); 9a OCH 2 Bu t (M ~Zr) 18 ], M(OBu t ) 2 (mmp) 2 ; 9a b-diketonates M(b-dik) 4 [b-dik ~acac (acetylacetonate), tfac (trifluoracetylacetonate), hfac (hexafluoracetylacetonate); 11b,14a thd (thd ~2,2,6,6-tetramethyl-3,5-heptanedionate) 9c,14,19 ]; as well as mixed-ligand species such as Zr(hfac) 2 [(MeCOCHC-(Me)LNCH 2 ) 2 ] 20 or [Zr(OR) 42x (b-dik) 22 ]. ''Y(acac) 3 '' 19a and Y(thd) 3 9c,11b,19a,23 have been used as Y precursors for deposition of YSZ films.…”

Deposition of yttria-stabilized zirconia thin films by atomic layer epitaxy from β-diketonate and organometallic precursors

“…Chemical vapor deposition (CVD) methods include spray pyrolysis, [39][40][41] electrochemical vapor deposition 42 as well as conventional, 43 aerosol 44 and plasma assisted CVD. [45][46][47] In the CVD processes, volatile zirconium precursors employed are typically the b-diketonates, such as Zr(thd) 4 [48][49][50] and Zr(acac) 4 , 51 (thd 2,2,6,6-tetramethylheptane-3,5-dionate and acac ~acetylacetonate) but also ZrCl 4 , 52,53 alkoxides 54,55 and compounds with tetradentate Schiff-base ligands 56 have been used. The selection of yttrium precursors has been more limited; only the use of Y(thd) 3 43,51 or YCl 3 52,53 has been reported.…”