A LATERAL INJECTION POROUS SILICON DEVICE STRUCTURE FOR LIGHT-EMITTING-DIODES

Lateral injection porous silicon (PS) diodes and metal-pg-metal(MPM) s tructures incorporated with PS-on-oxide structures are fabricated and characterized. The porous Si and the bottom oxide are formed in the sa me electrochemical cell but with different chemical solutions. The bot tom oxide provides good isolation for the current flowing in the PS re gion and the current density level is higher compared with the counter part without bottom oxide. Strong red-orange photoluminescence is obse rved under daylight, but the electroluminescence is weak owing to the lack of efficient hole injectors and the too thick gold contact films of the samples. A charging effect during electrical measurements and a punch-through-like behaviour at higher voltages are observed in the c haracteristics of MPM samples, suggesting a large number of traps and the ease of depletion in PS. The diode with bottom oxide is well behav ed except for the large series resistance. The PS-on-oxide technique i s shown to be beneficial for lateral porous Si devices.