METAL REACTIONS TO ANODIZED POROUS SILICON-CRYSTALS

Reactions of such metals as Ag, Au and Ti deposited over anodized porous silicon (PS) crystals have been investigated using electron spectroscopy techniques and Rutherford backscattering spectrometry. The results show that diffusion of metal atoms is significantly enhanced through the pores in PS. In the case of Ti, elevated substrate temperatures as high as approx. 550°C were required for a continuous growth of Ti silicides without surface accumulation of Ti. An alternative method, room temperature deposition followed by rapid annealing at 700-1000°C, was shown to be a good candidate for the metallization of PS with Ti. The presence of unreacted regions of PS under Ti silicides have been found to induce a thermal instability of stable compounds for a bulk Si-Ti system.