Selective area isolation of β-Ga2O3 using multiple energy nitrogen ion implantation
Appl. Phys. Lett., vol. 113, no. 17, pp. 172104 (2018).
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In this study, we report on the application of multiple energy nitrogen ion implantation for the electrical isolation of electronic devices on monoclinic β-Ga2O3. By the introduction of uniformly distributed midgap damage-related levels in the Ga2O3 crystal lattice, we are able to increase the sheet resistances by more than 9 orders of magnitude to ≥1013 Ω/sq which remains stable up to annealing temperatures of 600°C carried out for 60 s under a nitrogen atmosphere. At higher annealing temperatures, the damage-related trap levels are being removed causing a significant drop of the sheet resistance down to 4×105 Ω/sq for annealing temperatures of 800°C. This effect is preceded by a structural recovery of the implantation damages via the recrystallization of the crystal lattice at already 400°C as verified by x-ray diffraction measurements. The extracted activation energies of the deep states controlling the high resistivity of Ga2O3 after implantation are in the range of 0.7 eV, showing a strong correlation with the annealing temperature dependence of the sheet resistance and thus supporting the theory of a damage-induced isolation mechanism.
1 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, 12489 Berlin, Germany
2 Leibniz-Institut für Kristallzüchtung (IKZ), Max-Born-Str. 2, 12489 Berlin, Germany