Ion implantation induced swelling in 6H-SiC

Abstract

Ion implantation induced surface expansion (swelling) of 6H-SiC was investigated through the measurement of the step height between implanted and unimplanted areas. The samples were irradiated at room temperature with 500 keV Al+ ions in the dose range 1.25×1014–3×1015 ions cm−2. Swelling was related to dose and the area density of ion-induced damage measured by Rutherford backscattering channeling technique. The observed trend is consistent with the hypothesis that the volume expansion of the ion damaged crystal is proportional to the area density of displaced atoms, plus an additional relaxation occurring at the onset of the crystalline to amorphous transition.

Characterization of radiation damage in ceramics: Old challenge new issues?

“…PDFs are of prime importance for the study of amorphization in irradiated ceramics and the method has been used to discuss amorphization in SiC. 115 HRTEM also offers the opportunity to apply quantitative spectroscopic techniques like electron energy loss spectroscopy, 116 high angular resolution electron channeling, 117 or electron dispersive x-ray spectroscopy to quantify the concentration of species in ceramics over few nanometers. 118 The main limitation of TEM is due to the fact that observations must be performed on thin films.…”

Damage profiles and ion distribution in Pt-irradiated SiC

“…According to our previous study, increases in volume swelling after amorphization may be attributed to an increase of defect states and short-range chemical disorder in the amorphous layer [34]. Compared to results in the literature where an average volume swelling over the damaged region is used in correcting depth profiles [8,35,36], there is an advantage in using local EELS measurements. Since the local volume swelling can be determined from EELS, more accurate corrections in depth scale can be made by integrating the local volume expansions over depth.…”

Lattice mismatch and crystallographic tilt induced by high-dose ion-implantation into 4H-SiC

“…Ion implantation is usually employed for SiC device fabrication, since the diffusion constants of dopant atoms are extremely low. Although fundamental technology of ion implantation has been developed in the past decades, 3,4 ion implantation can leave serious damage in the lattice sites; generation of point defects 5,6 and structural defects, [7][8][9] polytype transition, surface swelling, 10 and amorphization. Excess interstitial atoms generated by ion implantation can migrate during post-implantation annealing, resulting in the formation of clusters and platelet defects.…”

“…[7][8][9][11][12][13] Surface swelling was found to be proportional to the area density of displaced atoms in addition to the amorphous transition. 10 These implantation-induced defects can remain in the crystal even after high-temperature annealing, and affect the carrier transport. 14,15 High-dose ion implantation ð> 10 15 cm À2 Þ is required to achieve lower contact resistance at the region where metal contacts are formed.…”