Deep Electron Traps in n-InP Induced by Plasma Exposure

Deep electron traps in n-InP introduced during helium (He)- or hydrogen ( H2)-plasma exposure have been studied by means of isothermal capacitance transient spectroscopy (ICTS). Two electron traps, (Ec-0.51 eV) and (Ec-0.54 eV), which are designated E2 and E4, respectively, are detected at and near the surface treated with He plasma. These traps induced by He-plasma exposure can be passivated with hydrogen. When the samples are treated with H2plasma, E2 traps are only partly active and E4 traps are not detected due to being totally passivated with hydrogen. The density of E2 traps near the sample surface treated with H2plasma is strongly enhanced by applying reverse bias at room temperature because of dissociation and removal of passivating hydrogen. In contrast, hydrogen-passivated E4 traps become reactivated only by thermal annealing. An isochronal annealing experiment for the He-plasma-treated samples shows the first-order annealing process of E2 traps with the activation energy and the attempt-to-escape frequency of 1.5 eV and 3.2 ×1014s-1, respectively. The thermal dissociation process of hydrogen from E4 traps follows first-order kinetics and its dissociation energy and attempt-to-escape frequency are 1.65 eV and 4.9 ×1013s-1, respectively.