Annealing and activation of Si implanted InP

Abstract

The recovery of implant damage, and the activation of Si implanted into InP has been studied over a range of post-implant anneal temperatures from 295 to 1095 K. 600 keV Si+ ions were implanted to doses ranging from 3.6 × 1011 to 2 × 1014 cm−2, and the resultant damage monitored by the Rutherford backscattering/channeling technique. For InP(Zn) and InP(S) wafers of (100) orientation, and undoped metalorganic chemical vapor deposition epilayers grown on InP(Fe) semi-insulating substrates, spontaneous recovery of lattice damage occurs at 295 K. For Si doses ≤ 4 × 1013 cm−2, up to 70% of the initial damage (displaced atoms) annealed out over a period of ≊85 days. The degree of recovery was found to depend on the initial level of damage. Recovery is characterized by at least two time constants; t1 < 5 days and t2 ≊ 100 days. Anneal rates observed between 295 and 375 K are consistent with an activation energy of 1.2 eV. Hall effect measurements following rapid thermal annealing of implanted epilayers, indicate that electrical activation commences at about 850 K; full activation is achieved by 1045 K, this process being characterized by an activation energy of 1.9 eV. The room temperature photoluminescence intensity, which remains almost constant for the unimplanted epitaxial InP over the full rapid thermal annealing (RTA) range, is extinguished after implantation and only recovers to about 18% of the value for the unimplanted reference material. This appears to be associated with the appearance of thermal etch pits which are most pronounced at the highest RTA temperatures and the higher implant doses. These etch pits are almost absent in the unimplanted material subjected to the same RTA cycles.