Surface Modification of Sputtered Ga.5In.5Sb Thin Films

Growth of Ga.5In.5Sb thin films was carried out using a in a r.f. magnetron sputtering system on high-purity quartz glasses as a substrate. The target material for the film was grown in the laboratory using Vertical Bridgmen method. The polycrystallinity of the sputtered films were characterized using x-ray diffraction method. The grown films were then treated with Ruthenium (Ru), Platinum (Pt) and Palladium (Pd) ions. XPS studies on the film showed the incorporation of Ru, Pt and Pd along with Ga, In and Sb. However in case of Ru and Pt treated surface a mild oxygen peak was also observed. No such oxide peak was observed in Pd treated surface. SEM studies on the films were also carried out which shows the increase in smoothness of the film after Ru and Pt treatment, whereas the surface deteriorated in case of Pd treatment. This can be interpreted as reduction in surface states induced by passivating oxide formed after Ru and Pt treatment. Electrical characterization of the film viz. Vander Pauw resistivity, Hall mobility etc. measurements also showed improved result compared to untreated and Pd treated surface and is been reported. Finally with chemically treated films Au/Ga.5In.5Sb Schottky diodes were fabricated and electrically characterised for IR detectors.