Damage Recovery and Dopant Diffusion in Si and Sn Ion Implanted β-Ga₂O₃

Abstract

The commonly used n-type dopants, Si and Sn, were implanted into bulk (−201) β-Ga 2 O 3 over a 2 order of magnitude dose range and annealed at temperatures from 1000-1150°C. The original lattice parameters were restored by annealing at 1150°C for the highest dose Si implants, while only partial recovery was observed in Sn implanted samples. The Sn implanted samples had overall lower lattice parameters compared to the Si implanted samples, indicating that Sn generates tensile strain in the Ga 2 O 3 lattice. The rocking curve FWHM was observed to increase with the annealing process, indicating that the annealing process does not improve the crystal quality. Transmission electron microscopy showed removal of the end-of-range lattice damage after 1150°C anneals of the heaviest implanted species, Sn. Cathodoluminescence at 5K showed recovery of intensity of the common UV band around 3.2 eV after annealing. Secondary Ion Mass Spectrometry profiling showed the presence of concentration-dependent diffusion of both Si and Sn, with values for diffusivity at 1150°C of 9.5 × 10 −13 cm.s −1 for Si and 1.7 × 10 −13 cm.s −1 for Sn obtained by fitting through the FLOOPS simulation package.

Activation energy of silicon diffusion in gallium oxide: Roles of the mediating defects charge states and phase modification

“…Indeed, Si doping was realized by ion implantation to fabricate low resistance ohmic contacts [10] and MOSFET channels [11,12]. However, despite the technological importance of Si for Ga2O3-based device fabrication, the literature data on Si diffusion in Ga2O3 are not fully systematic; in particular, the activation energy has not yet been reported, resulting in predominantly qualitative conclusions [10,13,14]. Indeed, Sasaki et al [10] studied Si ion implantation into (010) -Ga2O3 and observed that Si atoms start to diffuse after 1100 C anneals in This is the author's peer reviewed, accepted manuscript.…”

“…N2 atmosphere, while Si piles-up near the projected range (Rp). Meanwhile, Tadjer et al [13] studied Si diffusion in (-201) -Ga2O3 in O2 ambient and did not detected Si accumulation at the Rp for the temperatures 1150 C. Sharma et al [14] have also confirmed a strong influence of the annealing ambient on Si diffusion in (-201) -Ga2O3, demonstrating that the Si redistribution is significantly suppressed in N2…”

Cathodoluminescence Study of Damage Formation and Recovery in Si-ion-implanted β-Ga2O3

“…Ion implantation and activation annealing are key processes for the creation of an ideal local-carrier distribution in the device. Ntype regions have been successfully fabricated using Si-ion and other group-IV-ion implantations [8][9][10][11][12][13][14][15]. However, the damage generated by ion implantation may cause serious degradation and failure of the devices.…”

“…However, the damage generated by ion implantation may cause serious degradation and failure of the devices. Activation annealing can be used to activate dopant atoms and eliminate the generated crystal defects; however, such annealing may also diffuse the dopant atoms [10][11][12]14] and transform the point defects into more stable defects [12,14,16,17]. These changes during annealing may affect the device characteristics.…”

“…VUV excitation is effective for UWBG semiconductors; however, VUV systems require a special spectrometer and light source, and the operation conditions are only met in a synchrotron radiation beamline. Cathodoluminescence (CL), which uses electron beams, is suitable for defect characterization in UWBG semiconductors because conventional scanning electron microscope (SEM) can be used as the excitation source, and the exciting-beam energy exceeds the bandgap energies of UWBG semiconductors [11,[18][19][20][21][22]. We reported CL analysis on the Si-ion-implanted β-Ga2O3 [22]; however, only a cross-sectional measurement at a dose of 1 × 10 15 cm −2 , which was relatively high dose implantation, are show in in the report.…”