Method for calibrating an annealing furnace used to form thermal donors

A method for calibrating a furnace by determining an equivalent annealing time corresponding at least to a rise and a drop in temperature of the furnace so as to take into account a formation of thermal donors during heating and cooling phases of the furnace when a sample of semiconductor material is subjected to a first annealing in said furnace, the first annealing successively comprising the rise in temperature of the furnace, a first plateau at a set temperature and the drop in temperature of the furnace, the method comprising:

• a) providing a calibration piece comprised of the semiconductor material;
• b) determining the interstitial oxygen concentration of the calibration piece;
• c) subjecting the calibration piece to a second thermal donor formation annealing in the furnace, the second annealing comprising rise and drop in temperature of the furnace identical to those of the first annealing and a second plateau at the set temperature for a set time;
• d) determining the concentration of thermal donors formed in the calibration piece during the second annealing;
• e) determining the equivalent annealing time at the set temperature, corresponding at least to said rise and drop in temperature of the furnace, from the interstitial oxygen concentration, the thermal donor concentration of the calibration piece and the set time.