Patent ID: 7951692

Claim:
A method of producing a semiconductor substrate, which comprises the steps of: forming an oxide film having a thickness of not more than 50 nm on a wafer for an active layer, wherein the wafer has a surface side on which, a silicon layer is formed as the active layer; implanting ions other than hydrogen into the wafer for the active layer to a position shallower than an exfoliation region of the wafer for the active layer, implanting hydrogen ions into the exfoliation region to form a hydrogen ion implanted layer, laminating the wafer for the active layer through the oxide film to a wafer for a support substrate, and then exfoliating the wafer for the active layer at the hydrogen ion implanted layer; wherein the implanting of ions other than hydrogen is conducted to sputter a first quantity of oxygen from the oxide film; wherein the implanting of hydrogen ions is conducted to sputter a second quantity of oxygen from the oxide film; wherein the hydrogen ions are implanted after the implanting of ions other than hydrogen; wherein the first quantity of oxygen and the second quantity of oxygen are determined in consideration of total factor number producing an effect of suppressing hydrogen diffusion (N D ) expressed by formula (I) and N ID as follows: N D =N HO +N IO +N ID (I) wherein N D : total factor number producing an effect of suppressing hydrogen diffusion, N HO : oxygen introduced into the active layer through hydrogen ion implantation, N IO : oxygen introduced into active layer through ion implantation other than hydrogen, N ID : defects introduced into active layer through ion implantation other than hydrogen, and N D >4.2*10 14 atoms/cm 2 .