Defect mitigation by ion induced amorphousization and solid-phase epitaxy

Ion implantation is a common technique in the semiconductor industry used to modify the electrical properties of materials, usually silicon. Some dopant ions are sufficiently light, such as boron, that they do not create a continuous amorphous layer in silicon over the range of the ions. In the presence of such a layer, most of the ioninduced damage can be removed by solid-phase epitaxy growth (SPEG), which results in recrystallization of the amorphous damage. However, end-of-range defects at the amorphous-crystal interface give rise to threading dislocations during SPEG that degrade the quality of the recrytallized Si. We have studied the end of range defects in silicon with three different implantations. The first was with 80 keV 30Si with a dose of 3×1015 Si/cm2, and the second was with 100 keV 72Ge at a dose of 1×1015 Ge/cm2, and the third was a double implant of 100 keV 72Ge at a dose of 1×1015 Ge/cm2 followed by 340 keV 28Si at a dose of 3×1014 Si/cm2. SPEG was done at 650 °C to recrystalize the implanted samples, and the end of range defects were studied using channeled Rutherford Backscattering Spectrometry (RBS-c). The effects of photon-assisted hydrogenation on amorphization and recrystallization were also studied.