TEM characterization of phosphorus-implanted silicon

Abstract

Implantation of dopant-species into silicon can result in the formation of amorphous regions, interfaces and extended defects (in the silicon). The presence of these defects can cause modification of dopant distributions, and the rise of leakage currents in p-n junctions. An understanding of the behavior of implant-induced defects and their effect on dopant-distributions is therefore relevant. Such understanding could lead to better defect and dopant control and therefore to more reliable device performance. In this study, a correlation between dopant distributions and damage in implanted silicon, is investigated.The samples investigated were p-type (14-20 Ω-cm) silicon (100) wafers implanted with phosphorous at 180 kev to a dose of 1x1016 cm-2. The implants were performed at room temperature. Post-implant annealing was performed (by rapid-thermal annealing “RTA“) at 800°C for 15 seconds. SIMS (secondaryion mass-spectrometry) and XTEM (cross-section TEM) analysis were performed on as-implanted and annealed samples. Cross-section TEM specimens were made in the 110 geometry. TEM investigation was performed using a JEOL JEM 200CX transmission electron microscope operating at 200 kV. SIMS analysis was performed using an Atomika A-DIDA quadropole instrument with 8 keV O2+ primary ions.