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

Abstract

Channeling phenomena during ion implantation have been studied for 50 keV11B, 100 keV27Al and 240 keV71Ga in 4H-SiC by secondary ion mass spectrometry and medium energy ion backscattering. The same projected range is expected for the used energies while the channeling tails are shown to be substantially different, for example, channeled71Ga ions may travel 5 times as deep as11B. Ion implantation has been performed both at room temperature (RT) and at 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 for71Ga but nearly negligible for11B 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.