Study on the mechanism of Ge thin film exfoliation induced by H and He ion implantation

Abstract With the widespread application of smart-cut technology in thinning Ge wafers, uneven blisters and low exfoliation efficiency often occurred on the surface of Ge wafers. Therefore, it was necessary to investigate the influence of the implantation sequence of H and He ion on the delamination mechanism of Ge thin films. The physical mechanisms of surface morphology and internal defect evolution of samples implanted with H and He ions in different orders (H-alone, H first then He and He first then H) were systematically investigated by using various methods such as optical microscopy and transmission electron microscopy. However, with the increase of annealing temperature, the He-first sample had higher film exfoliation efficiency compared to the other two groups. The exfoliation of a large-area Ge thin film with a thickness of 656.4 nm had been achieved. In addition, the dynamic process of bubble and defect evolution inside samples co-implanted with H and He ions was analyzed at different annealing temperature stages. Finally, A physical model for surface blistering of Ge wafers implanted with H and He ions was established based on ion damage physics, gas diffusion dynamics, and thin film mechanics theory, which can provide quantitative prediction tools for the smart-cut process of Ge wafers.