Intentional and unintentional channeling during implantation of p-dopants in 4h-sic

Abstract

Channeling phenomena during ion implantation have been studied for 50 keV 11 B, 100 keV 27 Al and 240 keV 71 Ga in 4H-SiC by secondary ion mass spectrometry and medium energy ion backscattering. The same projected range are expected for the used energies while the channeling tails are shown to be substantially different, for example, channeled 71 Ga ions may travel 5 times as deep as 11 B. Ion implantation has been performed both at room temperature (RT) and 400 °C, where channeling effects are reduced for the 400 °C implantation compared to that of the RT due to thermal vibrations of lattice atoms. The temperature effect is pronounced for 71 Ga but nearly negligible for 11 B at the used energies. The channeling phenomena are explained by three-dimensional Monte Carlo simulations. For standard implantations, i.e. 4° off the c-direction, it is found that a direction in-between the [000-1] and the <11-2-3> crystal channels, results in deep channeling tails where the implanted ions follow the [000-1] and the <11-2-3> directions