The effect of dose rate and implant temperature on transient enhanced diffusion in boron implanted silicon

Modeling of the effects of dose, dose rate, and implant temperature on transient enhanced diffusion

“…During the high temperature anneal recombination is very efficient and most of the TED occurs in the plus one regime. After the postimplant anneal the total number of hops is independent of the dose rate, in agreement with the experimental results by Jones et al 4 A noticeable dependence of the number of interstitial hops during implantation on the dose rate is found at 400°C. This is due to the release of some free interstitials from small clusters that anneal slowly at 400°C.…”

“…9 However, in this temperature range, the number of interstitial hops during implantation is negligible compared to the total number of hops during the anneal. After the postimplant anneal the measured B diffusivity ͑proportional to the total number of hops͒ is approximately the same for all implant temperatures in this range, in agreement with Jones et al 4 For high implant temperatures ͑above 700°C͒, most of the damage generated in each cascade is annealed out during implantation. The residual damage is small, and there is little interaction between cascades; this is similar to the low dose regime.…”

“…1 This model implies that the Frenkel pairs rapidly recombine without contributing significantly to TED, and only the excess interstitial generated as the implanted ion becomes substitutional controls TED. Several experiments [2][3][4] and calculations 5 confirm the validity of this model for usual implantation conditions: light implanted ions ͑B, P, or Si͒, high doses (10 13 -10 14 ions/cm 2 ), high dose rates (Ͼ10 12 ions/cm 2 s), and low implant temperature ͑around room temperature͒. According to the ϩ1 model, the enhanced diffusivity is independent of the implanted ion, since all the ions generate only one excess interstitial.…”

“…6 Packan et al 7 have observed that the enhanced diffusivity increases sublinearly with the dose. Jones et al 4 reported that variations in the implant temperature, between 5 and 40°C, and beam current between 0.035 and 0.35 mA/cm 2 , do not influence the final amount of B diffusion after the postimplant anneal. However, Masters et al 8 have shown that both the dose rate between 10 11 and 10 13 protons/cm 2 s and implant temperature from 600 to 900°C, do influence B enhanced diffusion during implantation.…”