Effects of Helium Implantation on the Mechanical Properties of 4H-SiC

Abstract

The evolution of mechanical properties of helium-implanted 4H-SiC at room temperature has been mainly studied by nanoindentation tests. The curves of hardness and elastic modulus present a maximum at low levels of damage while a degradation of the mechanical properties is observed for high levels of damage. However, when the concentration of implanted ions exceeds 0.5 %, complex defects (helium-vacancy defects) become predominant which results in the increase of both the hardness and the modulus. Under high fluence of helium implantation tiny bubbles form and the amorphous transition is observed above a critical level of damage.