Porous silicon field emitters for display applications

A fabrication technology for porous silicon (PS) field emitters for display applications is described. Silicon blunt emitters prepared on p-type silicon wafers of 30 Ω cm resistivity were covered with a thin layer of porous silicon using an electrochemical anodization in ethanoic hydrofluoric solution. A PS layer with similar characteristics was also prepared on flat silicon surfaces. The PS layer morphology was investigated by scanning electron microscopy (SEM). The composition of the PS layers after the stabilization treatments was analyzed by secondary ion mass spectrometry (SIMS). Similar values of the vacuum field emission current were obtained for both cases of PS on silicon blunt tips and on flat surfaces. The oxidized porous silicon layers did not show vacuum field emission properties at all. Good field emission results were obtained on samples that were immediately processed to prevent the PS oxidation or on samples with a stabilized porous surface.