Fabrication of PbTiO3 and Pt self-organized nanocrystal array structure on atomically flat sapphire

The fabrication of ferroelectric nanocrystal materials such as Pb(Zr,Ti)O₃ has been widely researched because of the development of high capacity ferroelectric random access memory devices (FeRAM) and ferroelectric domain physics at the nano scale. The ultra flat surface of electrically conductive materials such as Pt is required for the deposition of the ferroelectric nanocrystal substrate. In this paper, Pt deposition was performed using our newly developed sputtering method (low angle incidence sputtering) on an atomically flat sapphire substrate. Due to Volmer-Waber growth, the sputtered Pt grew into island crystals at the normal deposition rate. However, lateral growth of Pt occurred at a very low rate, and the ultra thin atomically flat Pt layer could be obtained on the atomically flat sapphire surface. The Pt thin layer was also evaluated using electrically conductive atomic force microscope (C-AFM) measurement, confirming electric conduction of the atomically flat Pt layer. The obtained atomically flat Pt layer is expected to be utilized for electrical evaluation of PbTiO₃ nanocrystal array.