Sharp crack formation in low fluence hydrogen implanted Si <inf>0.75</inf>Ge<inf>0.25</inf>/B doped Si<inf>0.70</inf>Ge<inf>0.30</inf>/Si heterostructure

An approach to transfer a high-quality SiGe layer for the fabrication of SiGe-on-insulator wafers has been proposed based on the investigation of crack formation in H-implanted Si0.75Ge0.25/B-doped Si 0.70Ge0.30/Si structures. The crack formation is found to be closely correlated to the concentration of B atoms doped in the buried Si0.70Ge0.30 layer. For H-implanted Si 0.75Ge0.25/Si0.70Ge0.30/Si structures without B doping, no platelets or cracking is observed in the Si 0.70Ge0.30 layer. Upon increasing the concentration of B doping in the buried Si0.70Ge0.30 layer to 2 × 1019/cm3, cracking occurs at the interfaces on both sides of Si0.70Ge0.30 interlayer, thus, resulting in the formation of continuous sharp crack confined in the ultrathin Si 0.70Ge0.30 interlayer. With B doped ultrathin Si 0.70Ge0.30 interlayer, the Si0.75Ge 0.25 layer can be transferred to fabricate SiGe-on-insulator by H implantation with a fluence as low as 3 × 1016/cm2, which is only half of the typical fluence required for a conventional ion-cut process. Since cracking is confined in the ultrathin Si0.70Ge 0.30 interlayer, the as-cut SiGe-on-insulator possesses a rather smooth surface with a roughness of 1.55 nm. © 2013 AIP Publishing LLC.