Two signals in electrically detected magnetic resonance of platinum-doped silicon p–n junctions

We have found two electrically detected magnetic resonance (EDMR) signals at room temperature in forward-biased platinum (Pt)-doped (111) silicon p–n junction diodes with a linearly graded junction. The g values of the two EDMR signals are 1.991 (signal 1) and 1.978 (signal 2), respectively, when the surface of the diode is parallel to the magnetic field. The two signals increase after applying a large reverse-bias voltage to the junction. They decay with time; the decay rate after more than 1 h is smaller for signal 1 than for signal 2. The recombination current also changes in a similar manner as the EDMR signals. The intensity of the two EDMR signals each shows a known bell-shape dependence on a forward bias voltage; signal 1 is observed at slightly lower voltages than signal 2. The deep level transient spectroscopy (DLTS) spectrum from the diodes shows two peaks at 0.23 and 0.32 eV. For diodes with different Pt-diffusion temperatures, 865 and 885 °C, the ratio of the intensity of the EDMR signals corresponds to that of the platinum solubility in silicon, as does the ratio of the intensity of the DLTS peaks. Thus, we conclude that the two EDMR signals are related to the two Pt trap levels.