Preparation and Characterization of Copper-Tin-Oixde Thin Films Synthesized by Magnetron Sputtering
|Course||Microelectronics and Solid State Electronics|
|Keywords||Magnetron sputtering Copper-tin oxide films Perovskite structure Structure and optoelectronic properties|
Oxide semiconductor, in particular wide band gap semiconductor oxide material is important optoelectronic information material, it has a high transmittance in the visible region, having a high reflectance in the infrared region, the values ??of the conductivity close to the metal. Excellent photoelectric characteristics of the transparent conductive film has been widely applied in many fields of the solar cell, display, etc.. The wide bandgap semiconductor oxide material generally has a very large band gap is greater than 3.1eV, and can be used to produce a transparent electrode or blue or ultraviolet diode. Currently known centralized common transparent conductive oxide is a tin-doped indium oxide In 2 O 3 : Sn i.e. the usual said ITO, SnO , 2 < / sub>: F (FTO), SnO 2 : Sb (ATO) and so has very excellent optical and electrical properties of n-type transparent conductive film (TCO) film. However, due to the localized effect of the oxygen and the influence of oxygen vacancies, so that the p-type the TCO is difficult to achieve, and the absence of the p-type TCO limit the application of the TCO because the pn junction is a majority of the key structure of the semiconductor device. Until 1997, Kawazoe et al. Prepared out of the p-type CuAlO 2 transparent conductive film, it was obtained for the p-type the TCO certain breakthrough, since after the emergence of the batch delafossite structure copper Department of p-type transparent conductive oxides. SnO 2 is a direct band gap of a compound semiconductor, the room temperature bandgap of 3.6-4.3eV. The SnO 2 chemically stable, high temperature and transparent electronic devices suited to do, but little has been reported 2 p-type SnO If you get the SnO of the p-type 2 material will be the future of the photovoltaic device has an important influence in this context, we carried out research of the p-type tin oxide. The paper using magnetron sputtering method on quartz substrates prepared copper-tin oxide films by X-ray diffraction instrument (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), electron spectrometer (EDS), van der Fort methods on the structure and optoelectronic properties of copper-tin oxide films prepared study, systematic analysis of the reaction pressure, annealing conditions, sputtering substrate temperature for film growth rate, structure, transmittance and electrical The nature of the impact. XRD shows the prepared the copper tin oxide film on a quartz substrate, in the case of non-annealed amorphous thin film, when the annealing temperature reaches 530 ° C, the thin film crystal structure to change, a clear diffraction peak in the XRD patterns, With the annealing temperature increases, the diffraction peak width at half maximum (FWHM) narrowed, that the grain size becomes large. The reaction pressure also affects the film structure, and at the same annealing conditions, the reaction pressure becomes higher, the diffraction peak half-height width narrowing. Single crystal particles can be seen by the SEM in the surface of the film after annealing combined XRD database cards, these single crystal particles of the perovskite structure copper-tin oxide compound, the growth direction of (103) crystallographic orientation. TV1900 double beam UV - visible spectrophotometer reaction pressure and annealing temperature for the film transmittance. As the reaction pressure rise. The film transmittance elevated the highest visible light transmittance of more than 70%. Transmittance of the film after annealing than the unannealed film through rate, wherein the transmittance of films annealed at about 630 ℃ lowest obtained copper-tin oxide thin film, calculated by extrapolation bandgap before annealing and after annealing, respectively is 2.69 eV, 1.5eV. Use the Fan Petersburg methods to study the reaction pressure, substrate temperature and annealing temperature thin film electrical properties. Substrate heating film prepared under the same sputtering conditions, lower resistivity with the temperature of the substrate film not added. As the reaction pressure increases the film resistivity becomes high. Near 630 ℃ annealed copper tin oxide film film resistivity decreased. 0.5Pa reaction under a pressure of copper prepared tin oxide film, after annealing at 630 ℃ After 4 hours, the film resistivity was 66.3434Ωcm, carrier concentration, the Hall mobility were 6.42 × 10 16 sup> / cm 3 sup, 1.467cm of 2 sup> / Vs, film conductivity type is p-type. Use the Alpha the step meter test reaction pressure on the film growth rate, as the reaction pressure increases the film growth rate first increases and then decreases, thin film growth rate is the fastest in 1Pa reaction pressure of about 6.832 nm / min. Using a magnetron sputtering method on a quartz substrate to prepare a p-type copper-tin oxide thin film was found in the testing process, the reaction pressure, a sputtering the substrate temperature, the annealing conditions have a significant impact the nature of the film structure, and the photoelectric.