The Creation of Point Defects at Low Temperature

We mentioned above the collision cascade producing displaced atoms in a solid target. If we consider a single collision event in a crystalline solid, we can see that this displacement of atoms leads to the preferential formation of point defects. The most important types of point defects are a single vacancy (one atom or ion is missing), a single interstitial (an additional atom), a vacancy-interstitial pair (Frenkel pair). 

In addition to these defects di-vacancies, agglomerations of interstitials and extended clusters of point defects are well known. 

N = average number of displacements Eq = energy of the heavy ion Ej = average energy required to displace a lattice atom 

1 = contains other energy loss mechanisms apart 

This formula contains the assumption that energy transfer below the threshold for the displacement of one atom and between the threshold energy for the displacement of one atom and the threshold for the displacement of two atoms takes place via collisions which do not lead to the formation of point defects. 

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Chemical Effects of Ion Bombardment 2.6.1 The Creation of Point Defects at Low Temperature... 

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