Low-energy ion implantation technology and its application in materials research

Ion implantation technology, as an indispensable and crucial leading technology in the field of integrated circuit manufacturing, has developed over several decades. This technology utilizes the interaction between energetic ions and the material surface to produce lattice displacements at the microscopic scale, thereby creating defects and achieving changes in the structure and properties of the material. In recent years, with the continuous miniaturization of devices and the development of new functional materials such as two-dimensional materials and thin-film materials, low-energy ion implantation technology with an energy of less than 100 keV has begun to attract attention. Its applications in semiconductor, materials science, biomedical, and energy fields are also continuously expanding. As an advanced shallow doping technology, low-energy ion implantation can precisely control the types, range, dosage, and depth distribution of implanted ions, and as a non-equilibrium process not limited by solubility, it is suitable for surface modification of various materials such as metals, semiconductors, and insulators. The construction of low-energy ion implantation equipment is similar to that of conventional ion implantation machines, including an ion source, lenses, an analyzing magnet, a high-voltage platform, and an injection terminal. Since ions with lower energy ( are more susceptible to the influence of space charge effects during transmission, which results in the divergence of the ion beam spot and a decrease in transmission efficiency, and affects the injection effect, low-energy ion implantation equipment usually adopts a more compact structure. For ultra-low energy ion beams ( a method of first accelerating and then decelerating is required to ensure the transmission efficiency of the beam before implanting it into the sample. The low-energy ion research team at Peking University has developed a compact low-energy ion implantation system, which can be used for ion implantation experiments related to shallow doping and surface modification of materials. This system can provide multiple types of ion beams, implantation energies, and implantation doses with precise control within the energy range of 100 eV–100 keV. It can provide ion beams of dozens of gaseous or solid elements such as hydrogen and helium, with adjustable accelerating voltage from 10 to 100 kV, achieving an implantation dose range of 1012–1017 ions/cm2, an implantation area of 3 cm×3 cm, and is equipped with a temperature-controlled target platform, allowing for temperature control from room temperature to 950°C. The system has a compact structure, occupies less space, is simple to operate, and has good compatibility and scalability, making it highly suitable as a laboratory-level equipment platform for universities and other research institutions to research material doping and irradiation effects related to ion implantation. After its completion, it has been collaborated with domestic research teams to conduct material modification research based on low-energy ions in areas such as doping and modification of two-dimensional materials, perovskite-type thin-film materials, color center doping of quantum sensors, and the synergistic effect of irradiation damage in nuclear energy materials.