METHOD FOR DETECTING IMPURITY DURING GROWTH OF THIN FILM AND METHOD AND DEVICE FOR CONTROLLING COMPOSITION

PURPOSE: To enhance the surface flatness of a thin film of a compound or a complex oxide through strict composition control and to enable formation of a flat interface in a bonded and laminated structure, using a impurity detection/composition control method capable of on-site observation with high accuracy of quantitative determination and a device for executing the method. CONSTITUTION: This method for controlling the composition of a thin film of a compound or a complex oxide includes at least a process for performing on-site observation by means of reflection high-speed electron diffraction during the growth of the thin film of the compound or the complex oxide and for judging the constituents and the composition of impurities in the thin film being grown, by detecting a precipitated trace impurity phase; and a process for either decreasing the evaporation rate of excess elements or increasing the evaporation rate of insufficient elements; and this device is for executing the method.