Effect of implant temperature on secondary defects created by MeV Sn implantation in silicon

Abstract

Secondary defects induced by ion implantation in silicon after annealing have been previously shown to vary with the implantation and annealing conditions. However, in the low dose implants, well below the amorphization dose, the defects have been predominantly characterized to be interstitial in nature. In this article, we study the effect of implant temperature on secondary defects created by 1 MeV Sn implantation to a dose of 3×10¹³ cm⁻² after subsequent annealing. We report a variation in the defect microstructure with implant temperature showing preferential formation of small interstitial loops for −191 °C and only rod-like defects for similar implants carried out at 300 °C. We conclude that these microstructures are a result of the dense cascades created by heavy Sn ions, creating local amorphous pockets in the implant damage region at the lowest implant temperatures. The variation of the microstructure with implant temperature is interpreted in terms of the effect of dynamic annealing over the defects formed in silicon.