Hole traps of metastable iron-boron pairs in silicon

Hole traps of configurationally metastable iron-boron pairs in p-type silicon are studied using deep level transient spectroscopy, thermally stimulated capacitance, and single shot techniques combined with minority-carrier injection. Two levels at E_V+0.53 and 0.48 eV are observed as the metastable pairs after the injection at 150 K. The level at 0.53 eV consists of two traps vanishing with different decay rates at around 220 K, while the level at 0.48 eV annihilates with simple exponential form. The decay rate for each trap has a thermal activation energy of ∼0.7 eV and shows a single jump process of interstitial iron from one configuration to another. These new traps of iron-born pairs are discussed with the aid of configuration-coordinate description within the framework of the simple ionic model.