Step Coverage and Electrical Properties of (Ba, Sr)TiO₃ Films Prepared by Liquid Source Chemical Vapor Deposition Using TiO(DPM)₂

Abstract

Thin films of (Ba, Sr)TiO3 (BST) with high dielectric constant were prepared on Pt/ SiO2/Si substrates of 6-inch-diameter by liquid source chemical vapor deposition using Ba(DPM)2, Sr(DPM)2 and TiO(DPM)2 (DPM=dipivaloylmethanato; C11H19O2) dissolved in tetrahydrofuran (THF). The reproducibility of ±3 % for the film composition was achieved by optimizing the deposition procedures. It was found that the coverage of 72%, obtained at the substrate temperature T s=753 K, was better than those obtained using other Ti sources such as Ti(O-i-Pr)4 (TTIP) and Ti(O-i-Pr)2(DPM)2. The electrical properties of the 480-Å-thick BST film, deposited at T s=753 K using TiO(DPM)2, were as follows: dielectric constant ε=230, equivalent SiO2 thickness t eq=7.8 Å, leakage current density J L=6.7×10-6 A/cm2 at 1.65 V and dielectric loss tan δ=0.013.

Thermal Behavior of Ti(dpm)2(OiPr)2 Vapors

“…TiO(dpm) 2 , Ti(OR) 4 , Ti(dpm) 2 (OR) 2 , where dpm = 2,2,6,6-tetramethylheptane-3,5-dione, are among those used. [2±5] The comparative investigation of films obtained from different sources, such as Ti(OCH 3 ) 2 (dpm) 2 , Ti(dpm) 2 (O i Pr) 2 , Ti(O i Pr) 4 ( i Pr = isopropyl, (CH 3 ) 2 CH), has been reported.…”

(Ba,Sr)TiO3 Thin Films for Dram’s

“…The conformality of MOCVD BST has been studied as a function of the Ti precursor and has also been compared to sputter deposition, as shown in Figure 20 [54,74]. The BST conformality was evaluated for the following Ti precursors TiO(DPMh (titanyl bis (dipivaloylmethanato», Ti(0-i-PrMDPM)2 (bis (isopropoxy) bis (dipivaloylmethanato) titanium), and TTIP or Ti(0-i-Pr)4 (titanium tetraisopropoxide).…”

“…Deposition at lower temperatures produces good step coverage but the films asdeposited have inferior electrical properties [54,74]. In order to achieve better electrical properties, a two step process of depositing a thin film and then post annealing was developed.…”

Mass spectroscopic study for vaporization characteristics of Ba(TMHD)2 and Sr(TMHD)2 in electron cyclotron resonance-plasma enhanced metal organic chemical vapor deposition

“…Several deposition techniques, such as rf-sputtering, [1][2][3] reactive coevaporation, 4 and metal organic chemical vapor deposition ͑MOCVD͒ [5][6][7][8][9][10] have been reported for SrTiO 3 and ͑BaSr͒TiO 3 films. Among these techniques, MOCVD is often considered to be the best for its high deposition rate, easy composition control, easy scale up to manufacturing volumes, and excellent coverage of surface irregularities for high density DRAM application.…”