AVS 65th International Symposium & Exhibition
    Electronic Materials and Photonics Division Monday Sessions
       Session EM+AM+NS+PS-MoA

Paper EM+AM+NS+PS-MoA1
Area-Selective Deposition of Crystalline Perovskites

Monday, October 22, 2018, 1:20 pm, Room 101A

Session: Atomic Layer Processing: Selective-Area Patterning (Assembly/Deposition/Etching)
Presenter: Brennan Coffey, University of Texas at Austin
Authors: E. Lin, University of Texas at Austin
M. Coffey, University of Texas at Austin
Z. Zhang, University of Texas at Austin
P.Y. Chen, University of Texas at Austin
B. Edmondson, University of Texas at Austin
J.G. Ekerdt, University of Texas at Austin
Correspondent: Click to Email
Epitaxial growth of crystalline perovskites enables opportunities in integrating perovskite properties into electronic and photonic devices. Pattern definition is a necessary step in many device applications and definition through etching can be problematic with titanium-based perovskites. We report a process to grow the perovskite film into the final patterned-dimensions through area-selective atomic layer deposition (ALD) followed by epitaxial regrowth from a crystalline substrate to form a single crystal perovskite film. Epitaxial barium titanate (BTO) films can be grown by ALD on strontium titanate (STO(001)) and STO(001)/Si(001) substrates. The substrates are coated with 40 nm of polystyrene (PS) and 185- and 264-nm UV light projected through a shadow mask is used to crosslink the PS under a N2 atmosphere. The unexposed PS is stripped using toluene to expose the STO surface. Amorphous BTO films are deposited by ALD at 225 °C on the PS-patterned STO(001) surfaces. The low temperature process prevents the degradation of the PS layer. The PS mask is subsequently removed with an oxygen plasma exposure step. Atomic force microscopy and scanning electron microscopy after BTO growth and crosslinked-PS removal demonstrate high fidelity pattern transfer in the BTO films. Reflective high-energy electron diffraction and x-ray diffraction show that the film crystallizes after annealing the sample in vacuum at ≥ 750 °C, with oxygen partial pressure of 1 x 10-6 Torr. Film orientation as a function of annealing temperature is established with transmission electron and piezoresponse force microscopy.