Low-temperature annealing of heavily ion-implanted layer

Crystallinity recovery, impurity activation and stress relief in a heavily ion-implanted layer by ultrahigh-vacuum ion-implantation during low-temperature annealing were investigated and the following results were obtained. The crystallinity of the layer heavily doped with arsenic ions was recovered at 550°C for 75 min and the impurities were activated sufficiently. Furthermore, the impurity level distribution supported the LSS theory and the maximum carrier concentration was 1.6 × 1020 cm−3. The reverse current of the p-n junction formed by this method was two orders of magnitude lower than that in a conventional device. In the p-n junction formed by continuous ion implantation of arsenic and phosphorus to relieve the stress in the implanted layer, the reverse current decreased further. When the stress was most relieved, the carrier activation rate was highest and the p-n junction reverse current was lowest.