Precise Nanoporous Silicon Formation Process for an Integrated LED Source

Abstract

We propose to use nanoporous (npSi)/Al Schottky structure to fabricate and integrate into a Si chip light emitting source. High current densities and high concentrations of hydrofluoric acid are generally needed during the electrochemical etching process to fabricate high porosity nanostructured silicon films. However, short process time of ultrathin films formation, toxic and aggressive reagents are serious concerns associated with it. Therefore, it is highly demanded to seek alternatives to fabricate ultrathin Si films using lower current densities at low F- ion concentration. We have developed an ultrathin nanoporous silicon fabrication process by electrochemical etching in ammonia fluoride solution. It was shown that highly uniform and ultrathin high porosity nanoporous silicon films can be fabricated under very low current densities and fluorine ion concentration in a reproducible manner