STUDY OF AG THIN-FILMS DEPOSITED ON POROUS SILICON

The experimental results of DC I-V measurements of Ag thin films on po rous silicon are presented. The 200 Angstrom thick Ag thin films were deposited by RF magnetron sputtering. The substrate is p-type anodized porous silicon containing a random fractal surface structure with var ious size dimensions. For comparison, Ag thin films were also deposite d on HNO3 oxidized porous silicon. All porous silicon samples were ana lyzed by X-ray diffraction, SEM, FL, and FTIR spectroscopy, before and after oxidation. DC I-V measurements were performed on the Ag thin fi lms. Nonlinear I-V behavior has been observed which can be explained b y the random tunneling junction network model. The nonlinear I-V behav ior strongly relates to the surface roughness which affects the tunnel ing effect at the interconnections of junction resistors. For a smooth surface of oxidized porous silicon, the deposited Ag thin films have a linear I-V relation in two current regions, but their resistances dr op sharply in two discontinuous steps. Fractal-like I-V behavior, whic h needs more detailed investigation, was also observed.