IRON RELATED DEFECTS IN QUENCHED SILICON

Abstract

The aim of our research project is to (i) develop a digital computerized DLTS system in the laboratory and (ii) study iron related defects in quenched silicon. In the first part of project, two main IEEE based components, capacitance meter and pulse generator are interfaced with a computer. A software in Visual C++ has been programmed for communication and acquisition of data. Preliminary test run using our DLTS system has been taken to establish the performance of the system. It is found that our system is working well so for as the test run and initial measurements are concerned. However improvement in software and supporting equipment is still needed to enhance and extend its working. In the second part of the project, quenched samples of silicon has been studied in detail using a commercial DLTS system available in the department. At least two deep levels at energies Ee-0.55, and EcO.25 eV are observed in high concentration. The annealing characteristics of the two states EeO.55 and EeO.25 eV were measured. The annealing characteristics of Ee-0.55 gold related acceptor level showed the contribution of signal due to iron in a peak con-esponding to energy position Ee 0.55 eV. The other energy state at Ee-0.25 eV is identified as iron-gold complex. The characteristics of these two defects also suggest that they are pinned together. The comparison of emission rate signatures and annealing characteristics revealed that energy state at EeO.55 eV is due to gold acceptor and energy state Ee-0.25 eV is due to iron-gold complex. The inadvertent gold and iron are present in the samples.