Effect of annealing ambient on SiGe layer formation using Al–Ge paste for III–V solar cell application

Abstract

A mixed paste of aluminum (Al) and germanium (Ge) (7:3) was prepared and screen-printed on silicon (Si) substrates, followed by annealing at a peak temperature of 1000 °C in an infrared rapid thermal annealing furnace to investigate the liquid-phase growth of silicon-germanium (SiGe) epitaxial layers. The gas ambient during annealing was changed to investigate the effect on SiGe layer quality and physical properties. The SiGe-formed samples were observed by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). Oxygen-containing atmosphere suppressed the SiGe layer formation by oxidizing the Al particle surface limiting the reaction of the particle to the Si surface. On the other hand, annealing in an argon atmosphere without oxygen resulted in the formation of SiGe layers with a thickness of over 30 μm.