Diffusion of Impurities in the Semiconductor Melt

A new process for the production of n p n or p n p junction crystals is developed. In this process, n type single crystal of silicon is contacted to the molten silicon doped with suitable amount of donor and acceptor impurities. These impurities diffuse simultaneously from the melt directly into the crystal. In the case of silicon acceptor impurity has a higher diffusivity than donor impurity. So the n p n junction crystal is produced. An analysis of experiments using the following model is giver: solute diffusion layer exists directly under the melting crystal. Thickness of this layer is found to be 0.1 mm for the melting speed of 20 µ/sec and crystal rotation rate of 120 rpm. Similar experiment is carried out on germanium p n p junction.