The amorphization of 3C-SiC irradiated at moderately elevated temperatures as revealed by X-ray diffraction

Abstract

Mechanisms of radiation damage buildup in 3C-SiC remain poorly understood. Here, we use X-ray diffraction in combination with numerical simulations to study depth profiles of radiation-produced strain and lattice damage in 3C-SiC bombarded in the temperature range of 25-200 °C with 500 keV Ar ions. Results reveal increased defect recombination with increasing temperature, with a critical amorphization fluence increasing from 0.17 to 0.44 displacements per atom. The amorphization process is found to be correlated with the evolution of lattice strain. We find that, at fluences corresponding to the onset of amorphization, lattice strain is ~2% and is independent of temperature. With continuing bombardment above the onset of amorphization, the strain in the crystal bulk increases and reaches a saturation value that decreases from 7% to 5% with increasing temperature. Based on strain profiles, we compute depth profiles of the effective concentration of point defect clusters in the crystalline phase. Bombardment at higher temperatures results in lower maximum defect concentrations pointing to enhanced defect mobility.

Estimating the uncertainties of strain and damage analysis by X-ray diffraction in ion implanted MoO3

“…On the other hand, the average of the static DW factor continues to decrease with increasing fluence, reaching values close to zero for the fluences above 1×10 15 cm -2 . Similar strain and damage accumulation curves are observed in many ion implanted materials such as III-nitrides, III-V arsenides, cubic zirconia, and oxide materials (for example MgO, ZnO and UO2) [5,6,[8][9][10][11][12]14,23], where the strain saturation was attributed to the morphological alteration of the defect structures (from simple point defects to more complex defects), promoted by the high mobility of point defects during the implantation process. Figure 2 also shows the estimated uncertainties associated with the average strain and static DW factor values for each fluence, obtained by the method described in detail below.…”

“…[4] XRD has been used in many crystalline materials to investigate the strain introduced by implantation defects. [5][6][7][8][9][10][11][12][13][14][15] However, the estimation of the uncertainties associated with the strain and damage profiles is challenging since the fit results strongly depend on the considered fitting model. Therefore, simple statistical methods evaluating the goodness of fit may not be meaningful.…”

Lattice strain in irradiated materials unveils a prevalent defect evolution mechanism

“…The most common explanation for this strain relief is the formation of extended defects. Note that when irradiated at intermediate temperatures, amorphization is delayed or even prevented in semiconductors like Si or SiC, and strain relaxation also takes place by dislocation formation [43][44][45] . But this conclusion on the origin of the strain relaxation is based on additional observations with other techniques such as transmission electron microscopy (TEM) for instance 32-34, 36, 38 .…”

Interplay of the disorder and strain in gallium oxide

“…Notably, it is well established that the irradiation-induced disorder affects the strain level in the materials 9 . In semiconductors, the strain relaxation occurs most commonly via amorphization 10 , while the polymorphic transitions are rare 5 , 11 . To the best of our knowledge, Ga 2 O 3 is the only material where the irradiation induced polymorph transitions were demonstrated in a tractable way 5 , in contrast to the observations in other materials demonstrating much less controllable polymorphism 11 , 12 .…”