Effect of annealing conditions on dopants activation and stress conservation in silicon-germanium

Abstract

As the miniaturization of the size of semiconductor components, the silicon-based transistor has reached its material limitations, so that researching the new materials (silicon-germanium compound) to replace silicon is more important. The ion implantation technology is conducted to discuss the activation issue of p-type dopants, due to silicon-germanium epitaxial layer has the stress effect to enhance the carrier mobility, it is in a conflict of high-temperature annealing. In order to maintain the stress of the epitaxial silicon germanium layer and achieve the activation level of the carrier at the same time, this paper explores a new annealing method - microwave annealing (MWA) with the low thermal budget. In this study, we have investigated that using one-step microwave annealing energy in 3P (1P = 600W), which can make boron implanted into 30% Ge content of silicon germanium layer has the lowest sheet resistance (170 ohm/sq), the best epitaxial layer quality and the better residual stress index (1.48%). However, using two-step microwave annealing energy in 3P+1P over 100s, it can further achieve higher activation level for Si0.7Ge0.3: B sample without stress relaxation. (Sheet resistance as low as 134.6 ohm/sq, Hall measurement mobility of 302.7 cm2/Vs.).