The Role of the Nucleation Annealing Temperature Annealing on the Exfoliation of Hydrogen-Implanted GaN

Abstract

Exfoliation of ~1 µm thick GaN layers from bulk GaN or GaN / sapphire templates was achieved and is based on a study of the introduction and evolution of strain-related defects produced during hydrogen implantation. Hydrogen-implanted GaN at 77K produces two distinct strain-related regions. Analysis and modeling of the strain distribution via triple axis diffraction and SRIM calculations showed that one region is near the surface and the second at the projected range. After annealing at temperatures from 150 °C to 450 °C for extended times (1-40 hours), the near-surface strain reduces for all annealing conditions, whereas the strain in the peak from near the projected range decreased monotonically as the annealing temperatures increased to 300 °C but showed a reversal, i.e., a reduction in the strain at higher temperatures. This led to a two step exfoliation process with the low temperature step performed at either 150 °C or 375 °C for 20 hours followed by high temperature annealing ( > 650 °C). The first combination produced a series of small (< 1 µm) blisters whereas the 375 °C first step combination produced several µm-sized exfoliated sections (with removal of 1 µm thick layers). This sequence promoted the transfer of a thicker layer using a lower dose than had been reported previously.

Experimental evidence of auxeticity in ion implanted single crystal calcite

“…1 b along with the Ar + concentration and displacements-per-atom profile calculated using SRIM 16 . We observe that the resulting compressive strain profile generally follows the displacements-per-atom profile calculated from SRIM, and this is similar to what is observed with other implanted materials 7 , 17 , 18 . We find that different parts of the resulting strain model corresponds to different sections of the XRD ω:2θ measurement: (1) the shallow highly strained surface layer (~ 30 nm from the surface) corresponds to the rightmost fringe at ~ 400″ in the experimental XRD measurement, (2) the constant strain region that spans from ~ 30 nm to ~ 310 nm from the surface corresponds to the strain peak at ~ 310″, and (3) tail of the strain profile spanning ~ 310 nm from the surface to the bulk of the substrate past the implanted region corresponds to the fringes to the left of the strain peak (~ 100″ to ~ 250″).…”

“…In this study, auxeticity in calcite is experimentally verified for the first time—a property in calcite that had only been theoretically predicted 6 . While ion implantation has been previously used for other applications such as exfoliation and doping 7 , 9 – 12 , 17 , we employ ion implantation along with X-ray diffraction measurements to probe the mechanical properties of calcite. Fundamental understanding of the mechanical properties can be insightful for studies examining, for example, the effects of irradiation on the various constituents of concrete (e.g.…”

Exfoliation of β-Ga2O3Along a Non-Cleavage Plane Using Helium Ion Implantation

“…This anneal sequence was based on previous work on exfoliation via ion implantation with other semiconductor materials. 18,20,21,[25][26][27][28][29][30] The low temperature step is associated with He blister nucleation which could be correlated to changes in X-ray diffraction (XRD) ω curves and the higher temperature step is correlated with growth of the blisters. We attempted individual annealing steps at a series of low temperatures to assess the onset of blister nucleation.…”

“…If an implanted substrate is bonded to a handle substrate prior to any blister-inducing anneal, uniform wafer splitting can be achieved, resulting in a largearea thin layer transferred to a handle substrate. 17,18 The current literature and previous efforts have further extended the efficacy, analysis, and understanding of hydrogen or helium implantation to silicon, [23][24][25] germanium, 26 III-V materials, 18,[27][28][29] and II-VI materials 30 where controllable wafer-scale areas of thin layers for various semiconductor materials were successfully exfoliated and transferred. Using ion implantation for thin-film integration naturally fits in the large-scale setting, as outlined by Hayashi et al: 18 (1) hydrogen or helium ions are implanted in a substrate, (2) the implanted substrate and a handle substrate are direct wafer bonded, and (3) the bonded structure is annealed to promote exfoliation.…”

Investigation on thermodynamics of ion-slicing of GaN and heterogeneously integrating high-quality GaN films on CMOS compatible Si(100) substrates

“…The heavily damaged GaN region consists many plateau and cavity defects, and the thickness of this damage region is about 200 nm. The cavity defects are generated by the sequential annealing at 550 °C and 800 °C 44 . The high-temperature post-annealing accelerates the migration and accumulation of the residual nano-defects formed during the GaN transferring at 550 °C, and hence the cavity defects with large size are formed.…”