NOVELTY - The method comprises measuring (S10) heights of measuring points on a solid-liquid interface of a crystal material disposed in a crucible, and automatically optimizing (S20) a parameter of a crystal growing procedure based on the measured heights so that the solid-liquid interface maintains a dome shape with a curvature during the crystal growing procedure. In measuring step, probes are moved in an automated manner to different points on the solid-liquid interface to measure the heights of the measuring points respectively. The probe includes a main portion, and a probing portion.    USE - The method is useful for monitoring and controlling a crystal growth during a crystal growing procedure (claimed), where the crystal is mono-like silicon crystal that is useful in a solar cell.    ADVANTAGE - The method ensures economical growth of the crystal with excellent energy conversion efficiency, purity, yield and quality by monitoring and controlling growth of the crystal.    DETAILED DESCRIPTION - The method comprises measuring (S10) heights of measuring points on a solid-liquid interface of a crystal material disposed in a crucible, and automatically optimizing (S20) a parameter of a crystal growing procedure based on the measured heights so that the solid-liquid interface maintains a dome shape with a curvature during the crystal growing procedure. In measuring step, probes are moved in an automated manner to different points on the solid-liquid interface to measure the heights of the measuring points respectively. The probe includes a main portion, and a probing portion connected to the main portion. The main portion is movable along a measuring track and rotatable around an axis of the main portion. The probing portion has a tip that is: offset from the axis of the main portion; disposed for contacting the different points on the solid-liquid interface when the main portion is rotated around the axis of the main portion; and moved along the measuring track. In optimizing step, the parameter includes a heating power during the crystal growing procedure. INDEPENDENT CLAIMS are included for:    (1) an apparatus for monitoring and controlling a crystal growth during a crystal growing procedure; and    (2) a probe system.    DESCRIPTION OF DRAWING(S) - The diagram shows a flowchart of a method for monitoring and controlling a crystal growth during a crystal growing procedure.    Measuring heights of measuring points on a solid-liquid interface of a crystal material disposed in a crucible (S10)    Automatically optimizing a parameter of a crystal growing procedure based on the measured heights so that the solid-liquid interface maintains a dome shape with a curvature during the crystal growing procedure. (S20)