Deep states associated with oxidation induced stacking faults in RTA p-type silicon before and after copper diffusion

Abstract

Oxygen induced stacking faults (OISF) with an average penetration depth of 1 μm have been generated at a density of 2 × 10 6 cm −2 in the rapid thermal annealed (RTA) p-type Czochralski (Cz) silicon. The photoluminescence, the hole capture and emission from clean OISF and from copper diffused OISF samples have been investigated. A simple photoluminescence spectrum dominated by the D 1 line and a single broad deep level transient spectroscopy (DLTS) spectrum have been observed in a clean OISF sample. The broad DLTS signal has a trap level of 393–456 meV at a peak temperature of 201–212 K. The diffusion of copper into the OISF sample reduced the D 1 line intensity very significantly and modified the capture properties of OISF related deep state. Two other states appeared after long copper diffusion times. Any heat treatment at 410 K between 15–60 min increased the trap concentrations, and finally one of the peaks became dominant. This was related to the formation of copper rich silicides which produced extrinsic dislocation loops.