This article investigates the impact of nickel atom clustering, introduced via diffusion into polycrystalline silicon, on its electrophysical properties. The samples were mechanically and chemically treated, followed by nickel deposition and thermal diffusion at 1000 °C. Schottky diodes were fabricated, and DLTS measurements were performed across a temperature range of 20–300 K. Surface morphology was analyzed using Scanning Electron Microscopy (SEM). The results revealed significant differences in the number and depth of deep-level traps between nickel-doped and undoped samples.