| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of forming an extremely shallow junction which allows no damage on the surface of an electrode due to laser irradiation and also allows an easy control of laser irradiation conditions during annealing, even if excimer laser suitable for annealing is used and metal such as Al which has a low melting point than that of a substrate material, and has a small specific resistance is used when forming a pn junction in a shallow region of a substrate which has a large light absorption factor for short wavelengths. SOLUTION: An acceleration voltage is selected, and impurity ions are implanted in a depth of 40 nm or lower into an impurity doping region (4 and 5) on a semiconductor substrate (1) by ion implantation. Thereafter, on the surfaces of the electrodes (7) preliminarily formed on the semiconductor substrate, a reflection film (9) for reflecting ultraviolet light having a wavelength of 300 nm or shorter is formed. Then, by radiating laser light having a wavelength of 300 nm or shorter on the impurity doping region (4 and 5) to recrystallize the impurity doping region (4 and 5) and electrically activate the impurities. In the laser radiation process, laser beams are reflected on the surfaces of the electrodes and are not absorbed by the electrodes, resulting in preventing the damage of the surfaces of the electrodes and causing no change in electric characteristics.
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