Analyzing Transition Metal Defects in Silicon via Deep Level Transient Spectroscopy for Quantum Qubit Applications in Semiconductors

Quantum defects in semiconductors are critical for advancements in quantum sensing, computing, and communication. While defects in diamond and SiC have been extensively studied, silicon—a dominant material in microelectronics—has not been as well explored for quantum applications. Silicon's capability for large-scale manufacturing makes it ideal for scalable quantum computing. Desired quantum defects should have deep electronic levels far from the band edges, resembling isolated atoms, and be addressable by near-infrared light for spin-state control. Recent first-principles studies (Xiong et al., Sci. Adv. 2023; Lee et al., npj Comput. Mater. 2022) have begun identifying potential qubit hosts in silicon.

In our work, we investigated transition metal-related defects in silicon for quantum information processing. We fabricated MOS and Schottky diode devices, introducing transition metals like Ag, Fe, and Ti via thermal diffusion. Deep level transient spectroscopy (DLTS) was employed to examine the electronic properties, energy levels, and spin/optical modulations of these defects. These insights are crucial for engineering quantum defects in silicon using scalable microelectronics technologies.