Electrical barrier properties of meso-porous silicon

We present a contribution dealing with the study of the barrier properties of meso-porous silicon (PS) with metals and p+-Si crystalline silicon. Metal/PS/p+-Si and p+-Si/PS/p+-Si structures with different thickness (1–10 μm) of PS are investigated by means of current–voltage and capacitance–voltage characteristics combined with thermal stimulation in the 150–350 K temperature range. These experiments allowed a clear separation of bulk and contacts contributions to the electrical impedance. The barrier properties (nature and heights) of metal/PS contacts and PS/Si interfaces are then evaluated. The p+-Si/PS/ p+-Si structures exhibit ohmic contacts allowing space charge limited current (SCLC) ensured by carriers injection in the PS layers. From this analysis, the electrical behavior of the metal/PS/p+-Si structures is interpreted in terms of a Schottky barrier biased through a semi-insulating PS layer.