Tuning of Material and Electrical Properties of Strontium Titanates using Process Chemistry and Composition

Abstract

In this work, we study the compatibility of a highly volatile strontium precursor, HyperSr, which has a low melting point, good thermal stability and good reactivity, with various Ti precursors for atomic layer deposition (ALD) of strontium titanates (STO). Novel Ti precursors studied for STO deposition include PrimeTi & StarTi. We will then discuss the interesting trends in material properties observed in STO films deposited with various compositions. X-ray photoelectron spectroscopic analysis of ALD SrO films showed the presence of carbonate groups in the film. There is the potential that this carbonate species is inherent to the ALD process; however, it has been reported that SrCO3 forms when SrO films are exposed to atmospheric CO2. To isolate the effects of atmospheric exposure on the carbonate formation in the film, a TiO2 capping layer is used on the surface of ALD SrO films and the resulting film structures are analyzed.