Remote Plasma ALD of SrTiO[sub 3] Using Cyclopentadienlyl-Based Ti and Sr Precursors

Abstract

Remote plasma atomic layer deposition (ALD) of SrTiO3 films with different [Sr]/[Ti] ratios is reported, employing Star-Ti [(pentamethylcyclopentadienyl)trimethoxy-titanium, (CpMe5) Ti(O Me)3] and Hyper-Sr [bis(trisisopropylcyclopentadienyl)-strontium with 1,2-dimethoxyethane adduct, Sr (iPr3Cp)2 DME] precursors and O2 plasma. The as-deposited films were amorphous, but crystallized after post-deposition anneal above 500°C. For annealed SrTi O3 films with [Sr]/[Ti] =1.3 and a thickness of 50 nm, a high dielectric constant k>80 and low leakage current of ∼ 10-7 A/cm 2 at 1 V were obtained. It is demonstrated that changes in the composition and microstructure are apparent in the optical dielectric function of the SrTiO3 films, as obtained by spectroscopic ellipsometry. © 2010 The Electrochemical Society.