Deep-level transient spectroscopy (DLTS) measurements were performed on Si:Sb and Si:B n+-p step junction diodes grown by LT-MBE at various growth temperatures. The trap density dependence on growth temperature decreases with increasing temperature. However, segregation and diffusion increase with increasing temperature. Electron traps, E1 (0.42–0.45eV) and E2 (0.257eV), and hole traps, H1 (0.38–0.41eV), were found in B-doped layer grown at 370°C, 420°C, 500°C, and 600°C. These traps have been characterized by their capture cross-section, activation energy level, and trap density. The origins of the dominating electron traps are hypothesized as the association with pure divacancy defects. E1 level can be assigned for singly negatively charged divacancy V(0/-) + α and E2 level for doubly negatively charged divacancy V(-2/-).