Bistability of the BiOi complex and its implications on evaluating the “acceptor removal” process in p-type silicon

The dependencies of the B<math display="inline" id="d1e626" altimg="si183.svg"><msub><mrow/><mrow><mi mathvariant="normal">i</mi></mrow></msub></math>O<math display="inline" id="d1e634" altimg="si183.svg"><msub><mrow/><mrow><mi mathvariant="normal">i</mi></mrow></msub></math> defect concentration on doping, irradiation fluence and particle type in p-type silicon diodes have been investigated. We evidenced that large data scattering occurs for fluences above 10<sup loc="post">12</sup> 1 MeV neutrons/cm<sup loc="post">2</sup>, becoming significant larger for higher fluences. We show that the B<math display="inline" id="d1e649" altimg="si183.svg"><msub><mrow/><mrow><mi mathvariant="normal">i</mi></mrow></msub></math>O<math display="inline" id="d1e657" altimg="si183.svg"><msub><mrow/><mrow><mi mathvariant="normal">i</mi></mrow></msub></math> defect is metastable, with two configurations A and B, of which only A is detected by Deep Level Transient Spectroscopy and Thermally Stimulated Currents techniques. The defect’ electrical activity is influenced by the inherent variations in ambient and procedural experimental conditions, resulting not only in a large scattering of the results coming from the same type of measurement but making correlation between different types of experiments difficult. It is evidenced that the variations in [B<math display="inline" id="d1e665" altimg="si183.svg"><msub><mrow/><mrow><mi mathvariant="normal">i</mi></mrow></msub></math>O<math display="inline" id="d1e673" altimg="si316.svg"><msubsup><mrow/><mrow><mi mathvariant="normal">i</mi></mrow><mrow><mi mathvariant="normal">A</mi></mrow></msubsup></math>] are triggered by subjecting the samples to an excess of carriers, by either heating or an inherent short exposure to ambient light when manipulating the samples prior to experiments. For the samples investigated in this work both, the [B<math display="inline" id="d1e685" altimg="si183.svg"><msub><mrow/><mrow><mi mathvariant="normal">i</mi></mrow></msub></math>O<math display="inline" id="d1e693" altimg="si316.svg"><msubsup><mrow/><mrow><mi mathvariant="normal">i</mi></mrow><mrow><mi mathvariant="normal">A</mi></mrow></msubsup></math>] as determined from electrical spectroscopic measurements and the full depletion voltage as measured from Current–Voltage characteristics reach a steady state in <math display="inline" id="d1e713" altimg="si9.svg"><mo>∼</mo></math>7h. Any electrical measurement performed before will give a different result. The bi-stable behavior of the BiOi defect fully accounts for these variations. •The BiOi defect, causing the acceptor removal process in p-type Si, is bistable.•Only one BiOi configuration is detected by DLTS and TSC -BiOi<sup loc="post">A(0/+)</sup>.•The switch between the defect configurations can be triggered by ambient light.•After light exposure, it takes few hours for BiOi to stabilize in a stable state.•The BiOi introduction rate detected in DLTS and TSC experiments is underestimated.