PURPOSE: To reduce a crystal defect in a semiconductor substrate and to make it possible to obtain a good SOI structure by a method wherein as the condition for implanting oxygen ions in the semiconductor substrate, the acceleration energy of the oxygen ions of two times is set in 150 to 200KeV and moreover, the temperature of a heat treatment subsequent to the respective ion implantations is set at 1300°C or higher.
CONSTITUTION: Oxygen ions O+ are implanted in a first high-concentration n+ single crystal silicon semiconductor substrate (a semiconductor substrate) 23 from a first surface 2 toward a second surface 3. As the condition of implantation of the O+, the acceleration energy of the O+ of two implantations is 150 to 200KeV. The implantation amount of the O+ of the first implantation is 0.80×1018 to 1.30×1018cm-2 and the implantation amount of the O+ of the second one is 0.25×1018 to 0.50×1018cm-2 or 0.80×1018 to 1.30×1018cm-2. Moreover, the temperature of a heat treatment subsequent to the respective ion implantations is 1300°C or higher. Thereby, a crystal defect in the semiconductor substrate 23 is reduced and a Silicon On Insulator(SIO) structure of good crystal quality is formed.
MATSUMOTO SATOSHI
OONO AKIKAZU
IZUMI KATSUTOSHI
