Photoluminescence Characterization of Defects in Rapidly Annealed Ultra Shallow Junctions

Abstract

Defect formation and annihilation in ultra-shallow junctions (USJs), before and after rapid thermal annealing, are optically characterized by photoluminescence (PL) and UV Raman spectroscopy. Defect formation and annihilation in the USJ samples, by ion implantation and subsequent rapid thermal annealing, are characterized by transmission electron microscopy and deep-level transient spectroscopy (DLTS). It is confirmed that the defects are formed in the deep region beneath the ultra-shallow implanted layer. The defects degrade the PL intensity. The contribution of nonradiative recombination in the implanted layer was evaluated by PL measurements, after removal of the implanted layer, by repeated nano-meter scale wet etching. The PL technique clearly identifies defects formed in the deep region, i.e., the depletion layer. Compared with the results obtained by DLTS, PL measurements, conducted at room temperature, enable us to nondestructively characterize defects in the USJ, on an in-line basis, at a concentration in the order of 1012 cm−3 or below. This cannot be achieved by conventional techniques, such as the four-point probe method.