Defects left after regrowth of amorphous silicon on crystalline Si : C (V) and DLTS studies

Overview & Synopsis

n and p-type silicon have been self-ion implanted at 77 K with multi-energetic beams. This process was used to amorphize a 0.4 μm layer with a minimum amount of damage in the underlying crystal. After regrowth by a 550 °C anneal, the remaining defects were assessed by capacitance-voltage (C(V )) measurements and deep level transient spectroscopy (DLTS). In n-type Si, a buried layer of deep donors in large concentration was found, whereas in p-type Si, their concentration was small. These traps are believed to be associated with self-interstitials injected beyond the amorphous layer by the implantation process, their electrical activity depending on the nature of the majority carrier.