Effect of hydrogen implantation on the mechanical properties of AlN throughout ion-induced splitting

The ability to transfer bulk quality III-N thin layers onto foreign platforms is a powerful strategy to enable high-efficiency and low-cost optoelectronic devices. Ion-cut using sub-surface defect engineering has been an effective process to split and transfer a variety of semiconductors. With this perspective, hydrogen-implanted AlN samples were annealed in air at temperatures ranging from 300°C to 600°C for 5 min to study the influence of pre-layer splitting treatments on the nanomechanical properties. There is a clear dependence of the hardness on implanted hydrogen implantation fluence. We observe that the as-implanted hardness increased from 18 GPa for the virgin reference sample to ∼25 GPa for the highest fluence of 3 × 1017 H cm-2 prior to annealing. In the case of reference single crystalline Si samples, a significant drop in the hardness and elastic modulus is observed in the H implantation-induced damage zone subsequent to thermal annealing , while for crystalline epitaxial AlN samples with 0.5 × 1017 and 2.0 × 1017 H implant fluences, the hardness increases and peaks until the thermal annealing temperature reaches 350°C and subsequently begins to drop thereafter for higher annealing temperatures. However, for the 1.0 × 1017 H implantation fluence the hardness continues to increase with increasing thermal annealing temperature