IMPROVEMENT OF CRYSTALLINE QUALITY OF EPITAXIAL SI LAYERS BY ION-IMPLANTATION TECHNIQUES

We demonstrate that the crystalline quality of Si layers grown on sapphire substrate (SOS) by the CVD method can be greatly improved through the use of implantation of Si ions and subsequent thermal annealing at relatively low temperatures (∼550°C). This method utilizes an amorphous layer created by ion implantation near the sapphire/Si interface. Subsequent regrowth of this amorphous layer starting from the relatively perfect Si surface region leads to a much improved Si crystalline layer, as evidenced by MeV 4He + channeling and TEM measurements. When the implantation-formed amorphous layer is located at the outer portion of the Si layer, thermal annealing leads to only a small reduction in the amount of defects in the regrown layer as compared to the unimplanted sample. In these layers, epitaxial regrowth occurs with the same rate and activation energy observed in self-ion-implanted 〈100〉 Si.