Behaviour of Primary Defects in Electron‐Irradiated Germanium

Abstract

An investigation is made of the influence of the free electron and donor impurity concentrations on the annealing kinetics of the 36 and 66 "K stages and on the creation rate of the 36 OK stage, in low temperature electron irradiated n-type Germanium, using h-or Sb-doped samples, Ga and Cu compensated samples, and a Li-doped sample. The results obtained allow to conclude that the mobility of the Ge interstitial occurs at 4.6, 27, and 65 OK, depending on its charge state and the mobility of the vacancy at 90 OK, and to identify the defect associated with the 36 OK stage as a vacancy-interstitial pair where the interstitial is a donor impurity (annealing through the interstitial mobility). This interstitial mobility, strongly dependent on the charge state, explains radiation annealing and the behaviour of irradiated p-type Germanium.

Energy levels in electron irradiated n-type germanium

“…-Contrary to the case of silicon, defects in germanium have not yet been identified. At most there are good indications that when defects are produced by electron irradiation at low temperature in n-type material the vacancy-interstitial pairs recombine at 65 K [1] and that the 35 K annealing stage is connected with defects involving donor doping impurities [2]. The reason so little is known about defects in germanium is that spectroscopic technique either do not work (electron paramagnetic resonance) or have not been used extensively (IR absorption studies suggest that the vacancy becomes mobile at 90 K and forms the A centre [3]).…”

Electron and proton irradiation effect on the minority carrier lifetime in SiC passivated p-doped Ge wafers for space photovoltaics

“…We therefore compare our findings to similar studies in literature to find out about the nature of the irradiation defects. First of all, according to older literature, the introduction of irradiation defects into p-type doped Ge at room temperature was not expected [17,19,[33][34][35]. This is due to the fact that for the "classical" methods like EPR, DLTS and IR spectroscopy, some kind of [36,37].…”

Irradiation Induced Defects in III–V Semiconductor Compounds

“…The sccond way consists in examining in detail the kinetics of the pair annihilation. For long times, the annealed fraction varies as t -l i 2 which is characteristic of the recombination of correlated pairs, but not of close pairs [31].…”