Extended deep level defects in Ge-condensed SiGe-on-Insulator structures fabricated using proton and helium implantations

Abstract

SiGe-on-Insulator (SGOI) structures were created using the Ge condensation method, where an oxidation process is performed on the SiGe/Si structure. This method involves rapid thermal chemical vapor deposition and H+/He+ ion-implantations. Deep level defects in these structures were investigated using deep level transient spectroscopy (DLTS) by varying the pulse injection time. According to the DLTS measurements, a deep level defect induced during the Ge condensation process was found at 0.28eV above the valence band with a capture cross section of 2.67×10−17cm2, two extended deep levels were also found at 0.54eV and 0.42eV above the valence band with capture cross sections of 3.17×10−14cm2 and 0.96×10−15cm2, respectively. In the SGOI samples with ion-implantation, the densities of the newly generated defects as well as the existing defects were decreased effectively. Furthermore, the Coulomb barrier heights of the extended deep level defects were drastically reduced. Thus, we suggest that the Ge condensation method with H+ ion implantation could reduce deep level defects generated from the condensation and control the electrical properties of the condensed SiGe layers.