Deep levels of platinum in silicon
Platinum has received renewed attention of late from device engineers as a means of lifetime-control in silicon. The energy levels assigned to platinum are not well defined, however, and ambiguities exist in the literature. In this work platinum was introduced into n- and p-type silicon and the energy levels and concentrations studied by thermally stimulated current and capacitance techniques. p]Schottky barrier diodes were used to study electron emission from two levels found in the upper half of the band gap. The use of Schottky barriers eliminated the problem of process-induced defect introduced by high concentration p+ diffusions. Phosphorus-diffused n+ - p diodes were used to study hole emission from three levels found in the lower half of the band gap. Platinum concentration versus distance profiles were obtained from thermally stimulated capacitance measurements. Experimental results indicate that the platinum concentration follows the boron concentration distribution near the junction in p-type silicon.