Research on diameter control of Czochralski Silicon Single Crystal based on PSO parameter tuning for RNN-PFDL-MFAC

This paper addresses the issues of large diameter fluctuations and wire breakage in the Cz-si monocrystal. A real-time diameter control scheme for Cz-si monocrystal pulling, found on particle swarm optimization (PSO) parameter tuning for RNN-PFDL-MFAC, is proposed to achieve accurate diameter control. By analyzing the control parameters that affect the diameter of the Cz-si monocrystal, a three-input single-output RNN diameter prediction model is established for the isothermal stage of crystal growth. A real-time diameter control scheme for Cz-si monocrystal pulling is determined based on the prediction model, the PFDL data model, and the MFAC algorithm. The optimal values of hyperparameters in the control scheme are determined using the particle swarm optimization algorithm. Finally, the validity and stability of the control project are demonstrated by control simulation.