Thermal Behavior of Residual Defects in Low-Dose Arsenic- and Boron-Implanted Silicon After High-Temperature Rapid Thermal Annealing

Abstract

We investigated the thermal behavior of defects remaining in low-dose (<;10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">13</sup> cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> ) arsenic- and boron-implanted Si after high-temperature (1100 °C) rapid thermal annealing (RTA). The defects remaining after RTA were characterized as vacancy-type defects, and confirmed to be created by nonequilibrium states that occur during the extremely rapid cooling step of the RTA sequence. They were gradually removed by applying additional furnace annealing (FA) (i.e., thermal equilibrium heating process) at 300-400 °C. At the range of 500-600 °C, however, carbon- and oxygen-related point defects were newly created. These defects were confirmed to be eliminated at 700 °C, and the crystal quality was significantly improved. When using a rapid thermal process for heat treatment after low-dose impurity implantation, it is necessary to apply an equilibrium thermal treatment at >700 °C to remove residual damage as well as to activate impurities.