화학공학소재연구정보센터
Applied Surface Science, Vol.333, 1-12, 2015
Effects of growth temperature and target material on the growth behavior and electro-optical properties of ZnO:Al films deposited by high-rate steered cathodic arc plasma evaporation
ZnO:Al (AZO) films were deposited using high-rate (215 nm/min) steered cathodic arc plasma evaporation with a ceramic AZO target at various deposition temperatures (Td = 80-400 C). AZO films were also prepared with a Zn-Al target at various Td values for comparison. The high-melting-point (1975 C) AZO target significantly reduced the droplet size to -150 nm. In contrast, opaque Zn-Al microdroplets (several pm) were incorporated into the film deposited using the Zn-Al target. The incorporation of large microdroplets resulted in a rough surface and a nonuniform distribution of film thickness due to the selfshadowing effect. Using a combination of a ceramic AZO target and a steered arc to deposit AZO films significantly reduces the droplet size and maintains a high growth rate. The ratio of c- and a-axes lattice constants (c/a ratio) decreased with increasing Td. A higher c/a ratio facilitates strain relaxation via the formation of basal-plane stacking faults. The A11-1 doping efficiency was improved by increasing Td; however, the Al segregated to the grain boundary at high Td (>300 C). The films deposited with an AZO target at 200 C had the highest figure of merit (2.21 x 10-2 Q-1), with a corresponding average transmittance of 87.7% and resistivity of 5.48 x 10-4 S2 cm. (C) 2015 Elsevier B.V. All rights reserved.