Electron-beam-induced reactivation of Si dopants in hydrogenated GaAs: A minority carrier generation effect or an energetic electron excitation effect?

Abstract

We study the changes in electronic properties of Si-doped GaAs epilayers exposed to a hydrogen or a deuterium plasma, and then submitted to electron-beams of different injection energies (between 10 and 50 keV). Using Hall effect measurements, we have observed the formation of Si–H or Si–D complexes and their dissociation induced by the electron-beam irradiation. A strong isotope effect is observed in the dissociation rate of these complexes. Moreover, increasing injection energy reduces the dopant reactivation efficiency. Both effects are quite difficult to explain assuming minority carrier induced dissociation and could be understood under the light of recent works on electronic excitation of Si–H complexes in GaAs, and also of Si–H (D) bonds at the surface of silicon.