Ga segregation in Czochralski-Si crystal growth with B codoping

摘要

Codoping of gallium (Ga) and boron (B) in a Czochralski-silicon (CZ-Si) crystal has been proposed to be an effective way to improve the homogeneity of resistivity over the length of a simply Ga-doped Si crystal, by increasing the very small equilibrium segregation coefficient of Ga (k_0 = 0.008). It was observed that the axial resistivity variation in a Ga- and B-codoped Si crystal was smaller than that in simply Ga-doped Si crystals. The segregation behavior of Ga and B in the codoped CZ-Si crystal growth has been investigated in the present study. The effective segregation coefficient of Ga was kept almost constant when the B concentrations were low, but it increased at higher B concentrations. On the other hand, the effective segregation coefficient of B was kept almost constant when the B concentrations were low; however, it decreased at higher B concentrations. It has been analytically demonstrated that there is strong interaction between Ga and B in a Si crystal, which leads to an increase in the segregation coefficient of Ga in Si crystal growth.