Liquid Injection MOCVD of Zirconium Dioxide Using a Novel Mixed Ligand Zirconium Precursor

Deposition of ZrO2 and HfO2 thin films by liquid injection MOCVD and ALD using ansa-metallocene zirconium and hafnium precursors

“…Non-stoichiometric metal oxide films are often deposited by CVD techniques using metal alkoxides 24,25 and other precursors. 22,30,31 Stoichiometric metal oxide films can be readily obtained by post-growth annealing in air or oxygen at 600-1000 C. 9 The carbon incorporation found in the MOCVD deposited films using complexes 1-4 is more difficult to rationalise. The MOCVD HfO 2 films grown at 600 C using 3 and 4 31 and [(MeCp) 2 ZrMe(OR)] (OR ¼ OMe, OBu t ).…”

“…8 The alkoxide complexes [Zr(OBu t ) 4 ] 20 and [Hf(OBu t ) 4 ] 21 have been used successfully for the MOCVD of ZrO 2 and HfO 2 , but these unsaturated four-coordinate complexes are also highly moisture sensitive, and the deposited oxide films can sometimes be of low quality with a porous microstructure. The insertion of chelating b-diketonate ligands into the metal alkoxide complexes leads to more fully saturated, less moisture sensitive complexes such as the dimeric complex [Zr(OPr i ) 3 (thd)] 2 22 and monomeric [Zr(OPr i ) 2 (tbaoac) 2 ] (tbaoac ¼ tert-butylacetoacetate), 23 which allow the MOCVD of ZrO 2 with variable levels of carbon ($2-11 at.%). Similarly, the use of bidentate donor-functionalised alkoxide ligands, such as mmp (1-methyl-2-methoxy-2-methylpropanolate) and dmop (2-(4,4-dimethyloxazolinyl)propanolate), gives rise to the sixcoordinate complexes [M(OBu t ) 2 (mmp)] 2 , 24 [M(mmp) 4 ], 24 [M(OBu t ) 2 (dmop) 2 ] 25 (M ¼ Zr, Hf) and [Hf(dmop) 4 ], 26 which are significantly less moisture sensitive than the parent [M(OBu t ) 4 ] complexes, and these precursors have been used for the deposition of high purity ZrO 2 and HfO 2 films with excellent dielectric properties by liquid injection MOCVD.…”

Molecular design of improved precursors for the MOCVD of electroceramic oxides

“…The physical properties of [Zr(OPr i ) 3 (thd)] 2 are well-matched to those of [Pb(thd) 2 ] and, significantly, the optimum temperature range for oxide deposition from [Zr(OPr i ) 3 (thd)] 2 overlaps with that from [Pb(thd) 2 ], see Fig. 16. [Zr(OPr i ) 3 (thd)] 2 has proved to be a good precursor to ZrO 2 83 and superior to [Zr(thd) 4 ] for the liquid injection MOCVD of high uniformity Pb(Zr,Ti)O 3 . 26,84 A fluorinated mixed alkoxide/b-diketonate, [Zr(OPr i ) 2 (hfip) 2 ] (hfip ~hexafluoroisopropoxide), which is probably a monomeric six-coordinate complex, has also been proposed as a possible precursor for ZrO 2 and Pb(Zr,Ti)O 3 , 85 but trace fluorine contamination was observed under certain growth conditions in ZrO 2 films deposited by conventional MOCVD, which is a serious concern in microelectronics applications.…”

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“…CVD which has frequently been used for the deposition of ZrO 2 . Different types of precursors have been utilised in the CVD depositions of ZrO 2 including pure inorganics, 42,48,49 b-diketonates 2,25,50 and alkoxides 51,52 as well as mixed-ligand [53][54][55] and amido complex 56 compounds of zirconium. In addition, the CVD deposition of ZrO 2 has been reported from volatile organo-zirconium compounds, 1 including Cp 2 Zr(CH 3 ) 2 .…”