MULTISTAGE ANNEALING OF DEFECTS IN ION-IMPLANTED DOUBLE-BARRIER DIODES

The d.c. and a.c. characteristics of double-barrier diodes have been u sed to probe the large-scale annealing of defects within ion-implanted GaAs. Multi-stage annealing of defects was elucidated by the staged r ecovery of resonant tunnelling through ion-implanted diodes. Surprisin gly, the current-voltage characteristics of some ion-implanted diodes after very rapid anneals were qualitatively identical to the as-grown characteristics, but the peak-current density was two orders of magnit ude lower. This is explained by the creation of small percolation path s of as-grown material during the initial stages of annealing, where t hese paths surrounded clusters of defects. A simple capacitance model based on the creation of these percolation paths is described, and is consistent with the capacitance-voltage data. The idea that small-area percolation paths of as-grown material were created within the ion-im planted DBDs during very rapid annealing was supported by the observat ion of very-low bias resonant tunnelling and single-electron switching at 4.2 K. Both these phenomena are usually observed only within small -area pristine DBDs.