Single-crystal silicon has been amorphised by bombardment with Si+, Ge+ or Sn+ ions. After conventional annealing (900 degrees C, 30 min) some disorder remained. The amount was measured by ion channelling and transmission electron microscopy and compared with the quantity of excess interstitials predicted by the Monte Carlo computer program TRIM. Both the predicted and measured integral disorder fell as the atomic weight of the projectile increased. Because lattice strain also leads to a reduction in ion channelling this had to be taken into account when estimating residual damage from back-scattering analysis. The results indicate that there are six scattering centres per interstitial.
A band of disorder is observed following the annealing of surface amorphous layers produced by ion bombardment. The depth of the band's centre is just below the original amorphous/crystalline interface. The ion bombardment simulation computer program TRIM.CASCADE has been used in conjunction with ion channelling measurements to predict the areal density of atoms available for the formation of this band of disorder. The variation in the amounts of disorder expected due to changing the implantation parameters: ion dose, ion energy and implantation temperature are reported. The predictions are compared with the published transmission electron microscopy results and electrical measurements of other workers. The implications of this work for t h e technique of pre-amorphisation are also discussed.
Aligned and random ion channelling analysis was performed on p+n diode structures in (100) silicon, with the Surrey nuclear microprobe. Three different types of diode were investigated, each pre-amorphised by a different ion (Si+, Ge+ or Sn') before the p+ region was formed by BF,+ implantation. The ion channelling measurements are presented and compared with previously published electrical measurements on these diodes. Relatively large residual disorder and junction leakage currents were found for the Si+ pre-amorphised diodes; however, all the diodes were leaky ( > lo-6 A cm-2). The results are consistent with dislocation loops within the depletion regions of the diodes causing both the residual disorder and the large leakage currents. Crosssectional transmission electron microscopy studies support this model.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.