Energy damage

The simplest calculation of radiation damage involves only monatomic materials and has been described by many authors (17—20). For polyatomic materials, a calculation procedure for estimating damage energy from ion implantation has been outlined (8). The extension of this formalism (8) to direct calculations of damage energies in polyatomic materials has been addressed by several authors (11,21—24). 

It should be noted that the damage energy of a PKA with energy E, v(E), is closely related to the PKA s total nuclear stopping. This can be expressed as... 

To convert to vv s) values into laboratory damage energy vp( ), we will make use of the relationship... 

Fig. 13.5. Marker mixing data of several different markers in amorphous Si. This data shows (a) the relationship between the effective ion mixing diffusion coefficient, Dt, and ion mixing dose, tp, and (b) the effective mixing parameter, Dthp, and the damage energy deposited per unit length, FD (from Matteson et al. 1981)...

The primary features of (13.5) and (13.6) are that the effective diffusion coefficient should scale with the dose, , and the damage energy, Fu, in good... 

Equation (13.5) and the marker data presented in Fig. 13.5 can be used to estimate the average atomic displacement distance of a marker atom in a collision cascade formed in a matrix of amorphous Si. For example, from the temperature-independent data in Fig. 13.5a, a typical value of DiJlcj), for both Sn and Sb markers, is 4(10 cm" ), or 0.4 nm". From Fig. 13.5b, the corresponding damage energy is 1,500 eV nm Using the atomic density of crystalline Si, 50 atoms nm for the amorphous Si value of N, the ratio of Fj lN will be 30 eV nm This indicates that should be approximately 1.6 nm for a Si displacement energy of Ad = 13 eV. 

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