Advanced Precursor Development for Sr and Ti Based Oxide Thin Film Applications

Abstract

In this work, we evaluated novel Sr and Ti precursors for atomic layer deposition application. Traditional Sr precursor Sr(thd)2 is a solid with very low vapor pressure, high melting point, and requires high temperature oxidation for efficient carbon removal.. In comparison, bulky cyclopentadienyl based Sr compounds display high vapor pressures, low melting points, reactivity with water and high ALD growth rates. We also evaluated the effect of various stabilizing adducts on the properties of Sr cyclopentadienyl precursors and on the SrO ALD process. Sr precursors studied include AbsoluteSr Sr(iPr3Cp)2, HyperSr.THF Sr(iPr3Cp)2.2THF, HyperSr.DME Sr(iPr3Cp)2.DME, StarSr.THF Sr(Me5Cp)2.THF and StarSr.DME Sr(iPr3Cp)2.DME. Novel Ti precursors like PrimeTi (Ti(MeCp)(OMe)3), StarTi (Ti(Me5Cp)(OMe)3), TyALD (TiCp(NMe2)3) and StarTyALD (TiMe5Cp(NMe2)3) developed using heteroleptic chemistry are evaluated for TiO2 ALD. Finally, compatibility of the novel HyperSr.THF along with Ti precursors such as PrimeTi and StarTi in terms of composition tunability and material properties for STO ALD are studied.