Effect of temperature, illumination and frequency on the electrical characteristics of Cu/p-Si Schottky diode prepared by liquid phase epitaxy

Abstract

Microcrystalline thin Cu films were grown by liquid phase epitaxy, LPE on p-Si substrates. At the beginning of growth some of Cu atoms firstly reacted with Si forming a silicide layer (CuSi). After which a Cu film was epitaxially grown on the silicide seeds template which plays a key role in overcoming the lattice mismatch of Cu/p-Si. The topography of the grown Cu film on Si substrates was examined by scanning electron microscopy (SEM). The structural analysis by X-ray diffraction (XRD) confirmed a formation of Cu film as well as CuSi as an intermediate step. The current–voltage ( I– V) and capacitance–voltage ( C– V) characteristics of metal–semiconductor (Cu/p-Si) Schottky contacts were studied in the temperature range 300–375 K. The effect of the temperature on the series resistance R s , the ideality factor n and the barrier height Φ b were investigated. The Cu/p-Si diode shows non-ideal I– V behavior with an ideality factor greater than unity that can be ascribed to the interfacial layer, the interface states and the series resistance. The I– V characteristics of the investigated diode under high voltage region were found to be governed by space charge-limited currents. The extracted parameters were found to be strongly temperature dependent. The photocurrent properties of the device under illumination were also investigated. The photocurrent in the reverse direction is strongly increased by photo-illumination. In addition, capacitance–voltage–frequency ( C– V– f) characteristics were investigated at frequency range 10 kHz to 1 MHz. At each frequency, the measured capacitance decreases with increasing frequency due to a continuous distribution of the interface states.