Radiation tolerance of GaN: the balance between radiation-stimulated defect annealing and defect stabilization by implanted atoms

Abstract

Realization of radiation-hard electronic devices able to work in harsh environments requires deep understanding the processes of defect formation/evolution occurring in semiconductors bombarded by energetic particles. In the present work we address such intriguing radiation phenomenon as high radiation tolerance of GaN and analyze structural disorder employing advanced co-irradiation schemes where low and high energy implants with different ions have been used. Channeling analysis revealed that the interplay between radiation-stimulated defect annealing and defect stabilization by implanted atoms dominates defect formation in the crystal bulk. Furthermore, the balance between these two processes depends on implanted species. In particular, strong damage enhancement leading to the complete GaN bulk amorphization observed for the samples pre-implanted with fluorine ions, whereas the co-irradiation of the samples pre-implanted with such elements as neon, phosphorus, and argon ions leads to a decrease of the damage.

Ion Implantation into Nonconventional GaN Structures

“…A full loss of the single crystalline order is observed in regime V for very high fluences above 1 × 10 16 at/cm 2 . Similar curves were measured by several groups in c-plane GaN and AlGaN [38,50,51], nevertheless, it should be noted that, in some cases, chemical effects, as well as cascade density, can considerably change the defect accumulation in GaN [36,52,53].…”

“…The main conclusions can be summarised as follows: Due to efficient dynamic annealing effects, point defects can already recombine during the implantation keeping implantation damage low. In fact, a complete loss of single-crystalline order is only observed for implantation at cryogenic temperatures and very high fluences [35] or due to chemical effects, e.g., for fluorine implantation [36]. Nevertheless, the high mobility of point defects, even at low temperature [37], also leads to their interaction with each other or with native defects and, consequently, to the formation of thermally very stable point defect clusters and extended defects, such as stacking faults and dislocation loops.…”