Characterisation of Defects Induced by Ion-implantation Processing of P+N Shallow Junction Devices

The DLTS technique was used to characterise defects induced by ion-implantation processing in P+N shallow junction devices. BF2 implantation was carried out on silicon diodes pre-armophized by Ge at different energies. The variation of implantation energy and its effects on the type of defects generated and concentration of those defects across the devices were evaluated. From an electronic point of view, defects were categorised into two groups – that is shallow level and deep level defects. The results revealed that the higher the implant energy the more defects, of both types, generated in the device. Effectively, concentrations of both shallow and deep level defects in the devices increased as implant energy increased from 30 to 150 keV. The results also reveal that for low implant energy (30 keV) the defects are mainly the shallow level type and defectconcentration decreases with depth below junction. High energies (60 and 150 keV) show constant defect concentration across the sample thickness or depth.