Vacancy–donor complexes in γ-irradiated phosphorus-doped germanium

Abstract

It is shown that the n–p conversion of phosphorus‐doped Ge under γ‐irradiation is related to a concentration decrease of the P donor states. This might be explained by the fact that generated lattice vacancies can be trapped by substitutional atom impurities. An energy level introduced by γ‐irradiation could not be associated with the VP complex, thus the electronic states of this centre are obviously located in the valence band. The concentration of the (Ev + 0.12) eV acceptor level increases after the n–p conversion. This level is most likely associated with the donor–divacancy complex. When the “ultimate state” is achieved the Fermi level coincides with the group III acceptor level at 0 °K.

Production and Annealing of Defects in Proton-Irradiated n-Ge

“…At the beginning of irradiation the removal rate of shallow donors can be assessed around 215 cm -1 ; cf the calculated production rate of Frenkel pairs being around 400 cm -1 . As is seen, the kinetics features non-linear behavior like in the case of fast electron irradiation [4]. Such behavior is usually observed if there is more than one kind of defects formed.…”

“…Then n= f(1/T) curves can be analyzed using the statistics of charge carriers in non-degenerated semiconductors. The relevant equations can be found in many textbooks; see for instance [3] and related to n-Ge [4]. In this way one can determine the total concentration of shallow donor states of substitutional Sb atoms, N Sb total , taking into account all the energy states filled with and empty of electrons at T=0 K. It is very important that, together with N Sb total , the total concentration of all compensating acceptors at T=0 K, N a total , is also estimated.…”