We developed a surface-electrode ion trap with a square hole measuring \(40\,\mathrm {\mu m}\) for atomic loading. The hole was fabricated using anisotropic etching of a silicon substrate and was designed to minimize potential distortion in the trapping region. By introducing the atomic beam through the hole, we achieved enhanced isotope selectivity and experimentally demonstrated the selective trapping of calcium isotope ions using an atomic oven. We successfully prepared isotope ion pairs directly from the oven via sympathetic cooling at a rate comparable to that achieved using ablation loading. The sympathetic cooling process occurred on the order of a few seconds. We demonstrated the direct generation of an ion chain above the through-hole. This approach can be applied for trapping a wide range of ion species using a remarkably simple experimental setup, making it desirable for several applications such as quantum-charge-coupled-device (QCCD) architectures and precision measurements of isotope shifts.
