Effect of Electron–Phonon Interaction and γ-Ray Irradiation on the Reverse Currents of Silicon Photodiodes

Influence of formation conditions of silicon diodes on their reverse currents

“…In order to find the activation energies of recombination centers, an extrapolation procedure was carried out by the regression. In addition, it was taken into account that the generation current is limited by the electronic transition, which has the high activation energy [2][3][4]. To find the activation energy of the center through which the generation occurs, it is necessary to subtract the energy value from the band gap of silicon at 0 K, which is obtained by extrapolation to zero electric field strength.…”

“…In this region processes of generation of electrons and holes take place with participation of deep levels [1]. The generation is accompanied by the Pool−Frenkel effect, and this process is also influenced by the electron-phonon interaction, which leads to a smooth increase in the reverse current with increasing voltage [2][3][4]. From the point of view of the diffusion theory of the p−n junction current flow, the reverse current should not depend on the applied voltage [5].…”

“…The activation energy of the temperature dependence of diffusion current should be equal to the band gap energy of the semiconductor, but experimental studies show that this is not the case, and the activation energy is less than the band gap [2,6]. This is due to the fact that in most cases the reverse current is the sum of the diffusion current and the generation current [7], moreover the latter one is predominating [1][2][3][4]. The mechanism of current flow can be determined by studying its dependence on temperature.…”

“…This value must be calculated and compared with its experimental value in order to prove the existence of this effect. However, the Poole−Frenkel coefficient calculated from the experimental results may be larger than the theoretical one, which is due to the influence of the electron-phonon interaction [2][3][4]10]. The electron-phonon interaction can be significant when the recombination centers are complexes of several point imperfections.…”

“…Such complexes can contain different numbers of both vacancies and oxygen atoms [12]. They create recombination centers near the middle of the band gap in the band gap of silicon and actively influence the value of reverse currents [2][3][4]13,14]. While the influence of oxygen on the magnitude of the reverse currents of p−n junctions has been studied quite well, the influence of nitrogen has not been studied enough, and it affects both the formation of oxygen complexes [15] and creates deep levels itself in the band gap of silicon [12].…”