Erbium implanted silicon as a quantum technology platform has both telecommunications and integrated circuit processing compatibility. In Si implanted with Er to a concentration of 3 × 1017 cm−3 and O to a concentration of 1020 cm−3, the electron spin coherence time, T2, and the spin-lattice relaxation time, T1, were measured to be 7.5 μs and ∼1 ms, respectively, at 5 K. The spin echo decay profile displayed strong modulation, which was consistent with the super-hyperfine interaction between Er3+ and a spin bath of 29Si nuclei. The calculated spectral diffusion time was similar to the measured T2, which indicated that T2 was limited by spectral diffusion due to T1-induced flips of neighboring Er3+ spins. The origin of the echo is an Er center surrounded by six O atoms with monoclinic C1h site symmetry.
