Radiation-induced defect accumulation and annealing in Si-implanted gallium oxide

Abstract

Defect accumulation and annealing phenomena in Si-implanted monoclinic gallium oxide (β-Ga2O3) wafers, having [Formula: see text], (010), and (001) orientations, were studied by Rutherford backscattering spectrometry in channeling mode (RBS/c), x-ray diffraction (XRD), and (scanning) transmission electron microscopy [(S)TEM]. Initially, the samples with different surface orientations were implanted with 300 keV 28Si+-ions, applying fluences in the range of 1 × 1014–2 × 1016 Si/cm2, unveiling interesting disorder accumulation kinetics. In particular, the RBS/c, XRD, and (S)TEM combined data suggested that the radiation disorder buildup in Si-implanted β-Ga2O3 is accompanied by significant strain accumulation, assisting crystalline-to-crystalline phase transitions instead of amorphization. Selected samples having [Formula: see text] orientation were subjected to isochronal (30 min) anneals in the range of 300–1300 °C in air. Systematic RBS/c and XRD characterization of these samples suggested complex structural transformations, which occurred as a function of the fluence and the temperature. Moreover, a detailed (S)TEM analysis of the sample implanted with 2 × 1016 Si/cm2 and annealed at 1100 °C was enhanced by applying dispersive x-ray and electron energy-loss spectroscopies. The analysis revealed silicon agglomerations in the form of silicon dioxide particles. Signal from silicon was also detected outside of the agglomerates, likely occurring as substitutional Si on Ga sites.

Radiation Damage Accumulation in α-Ga-=SUB=-2-=/SUB=-O-=SUB=-3-=/SUB=- under P and PF-=SUB=-4-=/SUB=- Ion Bombardment

“…It is seen clearly that the differences in degree and distribution of damage induced by atomic and molecular ions are very significant. Conspicuous is the fact that the irradiation doses needed to produce detectable damage in the RBS/C spectra for the α-phase are appreciably higher than the corresponding doses for the β-phase (see, e.g., [18,20,25,26]).…”

In situ atomic-resolution study of transformations in double polymorph γ/β-Ga2O3 structures

“…Importantly, the parameters controlling the polymorphism in a macroscopic sample (typically used in the ex situ annealing experiments in the literature 8,22 ) and in a TEM-lamella sized sample (as used in this work) -may be different. Consequently, there could be potential discrepancies between the in situ and ex situ observations.…”

“…Similar implantation conditions were used previously in the literature for fabrication of double γ/β-Ga 2 O 3 polymorph structures. 9,10,22…”

Накопление структурных нарушений при облучении α-Ga-=SUB=-2-=/SUB=-O-=SUB=-3-=/SUB=- ионами P и PF-=SUB=-4-=/SUB=-

“…Участвующий в образовании оксида галлия кислород подавался в зону реакции, использовался газ ВЧ (99.998%). Рост слоев оксида галлия проводился при температуре подложки T ∼ 500 [18,20,25,26]).…”