Modification and Modeling of Ni/Si Interface for Photodetector Applications

We have demonstrated with both experiment and simulation, the method to modify the current response of n type silicon photodetector. The application of ultra-cooling temperature treatment (77 K) at various cooling times (15-60 minute) has been shown to significantly modify surface properties of n type silicon (100). The surface roughness of the untreated and treated samples was obtained using AFM techniques. Treated Si sample have better surface uniformity than untreated sample. The nickel (Ni) metal contacts were then deposited on the samples followed by current-voltage (I-V) characterisation. Treated samples showed increased dark and light currents compared with untreated sample. However, current gain (ratio of light to dark current) of some of the treated sample is enhanced while some are reduced compared with that of untreated sample. The simulation software ATLAS in SILVACO package is used to describe the effect of Ni/Si interface properties on its photodetection.