Influences of a Crystalline Seed Layer during Atomic Layer Deposition of SrTiO[sub 3] Thin Films Using Ti(O-iPr)[sub 2](thd)[sub 2], Sr(thd)[sub 2], and H[sub 2]O

Abstract

In situ crystallized similar to 20 nm thick SrTiO(3) (STO) thin films were deposited by atomic layer deposition at a growth temperature of 370 degrees C using a 3 or 5 nm thick crystalline STO seed layer before depositing the main layer. The influences of the annealing temperature used to crystallize the seed layer on the structure and electrical properties of the entire STO film were investigated. There was an optimum annealing temperature (650-700 degrees C) for achieving the optimum electrical performance. When the annealing temperature was < 600 degrees C, the crystallization of the seed layer was weak, and this resulted in poor in situ crystallization of the main-layer STO. On the other hand, annealing temperatures >750 degrees C induced adverse chemical interactions between the seed STO and Ru electrode, which inhibited in situ crystallization of the main layer when the seed-layer thickness was 3 nm. A slightly thicker seed layer (5 nm) was necessary for achieving a well-crystallized STO film when the seed annealing temperature was 750 degrees C. (C) 2008 The Electrochemical Society.