Efficient and ballistic cold electron emission from porous polycrystallinesilicon diodes with a porosity multilayer structure

Based on the previous investigations of the cold electron emission from por ous silicon and porous polycrystalline silicon (PPS) diodes, we have fabric ated PPS diodes with a porosity multilayer structure and evaluated the emis sion characteristics. The multilayer structure has functions of reforming t he electric field distribution and improving the thermal conductivity of th e PPS layer. It is demonstrated here that the multilayered sample exhibits high emission current density of similar to0.8 mA/cm(2) and high efficiency of similar to1%, which are close to values required for practical use. The emission is quite stable even with a high emission current density. Ballis tic electron emission mechanism is discussed in relation to the energy dist ribution of emitted electrons. (C) 2001 American Vacuum Society.