Studies Of Induced Defects And Its Optical Properties In Ion-implanted 6H-SiC

Ion-implantation is one of the important technologies of making semiconductor devices and integrated circuits (ICs). It has been developed very well in silicon processes, but there is still some work to be done for silicon carbide (SiC). In this paper, ellipsometry, Raman spectroscopy and optical absorption spectroscopy were used to study the induced defects and its optical properties in the ion implanted 6H-SiC. These measurements are powerful techniques, because they are simple, non-destructive and no special preparation of samples, which make it possible for us to monitor in situ.The refractive index n and the reflectance R, which were measured with ellipsometry, were able to show the degree of damages and the re-crystallization after annealing. The n and R increased with the degree of damages, therefore, it could be used to evaluate the degree of amorphization. For the N* and P+ ions implanted samples, the value of n and R were recovered after annealing at 1200℃, which showed the damages disappeared.Raman spectra indicated that the damages were light for samples of the N+ implantation, but the damages induced by the P+ and B+ implantation were serious. The damages in the N+ and P+ implanted samples were annealed out at 1200癈, which was consistent withresults of ellipsometry. However, the damages induced by B+ implanted 6H-SiC existed until 1600℃ annealing.The optical absorption spectra of ion implanted 6H-SiC samples had showed three aspects: the first was the increase in absorption near the intrinsic absorption band, the second was the elevation of the absorption baseline and the last was the red-shifting of absorption band edge. All of them were concerned with the degree of damages. These phenomena would be very obvious if the damages were serious. They would almost recover as well as those of the un-implanted samples after high temperature annealing.Three methods mentioned above are powerful technique for studying the damages induced by the ion implantation in 6H-SJC and its annealing behaviors. Their results are agreed with each other.