Method for evaluating quality of oxide semiconductor thin film, method for managing quality of oxide semiconductor thin film, and device for manufacturing semiconductor using said method for managing quality

A quality evaluation method for an oxide semiconductor thin film comprising:

• a first step, which comprises;
• irradiating a sample having an oxide semiconductor thin film formed thereover with excitation light and microwave to measure a maximum value of reflectance of the microwave from the oxide semiconductor thin film;
• subsequently stopping the irradiation with the excitation light;
• measuring temporal reflectance of the microwave from the oxide semiconductor thin film with the lapse of time after the stopping of the excitation light irradiation;
• and recording the reflectance of the microwave as a signal value for each of elapsed times (μsec) after the stopping of the excitation light irradiation;
• and
• a second step, which comprises;
• selecting a peak value having a largest calculated value and a time constant (μsec) for the peak value among calculated values obtained by substituting each signal value for respective elapsed times after stopping the excitation light irradiation and the corresponding elapsed time into the following Equation (1);
• and estimating, from the peak value and the time constant, an energy level of defect state and the defect density existing in the oxide semiconductor thin film:
• x=(signal value)×(elapsed time for the signal value) Equation 1,
• wherein
• x:
• calculated value,
• signal value (mV):
• reflectance of the microwave, and
• elapsed time for the signal value:
• time (μsec) which has elapsed from the stopping of the excitation light irradiation to the signal value.