Effects of Thermal Annealing on In Situ Phosphorus-Doped Germanium $\hbox {n}^{+}/\hbox {p}$ Junction

In this letter, we investigate the electrical behavior of vacancy V_Ge defects in Ge at various thermal annealing conditions through electrochemical capacitance-voltage analysis. Then, the effects of the annealing process on Ge n⁺/p junction diodes were also studied with J-V, transmission electron microscopy, and secondary ion mass spectroscopy measurements in the aspects of point-defect healing and dopant diffusion/loss phenomena. The V_Ge defects tend to heal by recombining with Ge interstitial atoms as the annealing process temperature increases. However, the diffusion/loss problems of P atoms in Ge become severe at above 500^°C. Therefore, an optimal postfabrication annealing process at 600^°C is proposed in terms of point-defect healing and dopant diffusion/loss reduction.