Growth of tr6-CaSi2 thin films on Si(111) substrates

Uniform and high-quality tr6-CaSi2 films were successfully grown via the co-deposition of Ca and Si on a Si(111) substrate. Using reactive Ca deposition, the films tended to form mixed phases of orthorhombic CaSi and two trigonal CaSi2 (three-layer repeat: tr3-CaSi2; six-layer repeat: tr6-CaSi2) structures at low substrate temperatures below 580 degrees C. A tr6-CaSi2 film was formed when the substrate temperature and thickness of the deposited Ca were controlled. By supplying an external source of Si along with Ca deposition, the formation of CaSi and tr3-CaSi2 was suppressed. and single-phase tr6-CaSi2 was obtained. (C) 2018 The Japan Society of Applied Physics