Patent ID: RE39484

Claim:
Process for the preparation of thin semiconductor material films, wherein the process comprises subjecting a semiconductor material wafer having a planar face and whose plane , is substantially parallel to a principal crystallographic plane, to the three following stages: a first stage of implantation by ion bombardment of the face of said wafer by means of ions creating in the volume of said wafer at a depth close to the average penetration depth of said ions, a layer of gaseous microbubbles defining in the volume of said wafer a lower region constituting a majority of the substrate and an upper region constituting the thin semiconductor material film, the ions being chosen from among hydrogen gas ions or rare gas ions and , wherein the temperature of the wafer during implantation being is kept below the temperature at which the gas produced by the implanted ions can escape from the semiconductor by diffusion, a second stage of intimately contacting the planar face of said wafer with a stiffener constituted by at least one rigid material layer, a third stage of thermally treating the assembly of said wafer and said stiffener at a temperature above that at which the ion bombardment takes place and adequate to create by a crystalline rearrangement effect in the wafer , a coalescence of hydrogen microbubbles and a pressure effect in the hydrogen microbubbles, a separation between the thin semiconductor material film and the majority of the substrate, the stiffener and the planar face of the wafer being kept in intimate contact during said stage.