Radiation damage and amorphization of silicon by 2 MeV nitrogen ion implantation

The disorders induced in crystalline silicon (c-Si) through the process of electronic energy loss in the swift heavy ion irradiation were investigated. A number of silicon <1 0 0> samples were irradiated with 65 MeV oxygen ions at different fluences, 1 × 10 13 to 1.5 × 10 14 ions/cm 2 , and characterized by the Raman spectroscopy, the optical reflectivity, the X-ray reflectivity, the atomic force microscopy (AFM) and the X-ray diffraction (XRD) techniques. The intensity, redshift, phonon coherence length and asymmetric broadening associated with the Raman peaks reveal that stressed and disordered lattice zones are produced in the surface region of the irradiated silicon. The average crystallite size, obtained by analyzing Raman spectrum with the phonon confinement model, was very large in the virgin silicon but decreased to <100 nm dimension in the ion irradiated silicon. The results of the X-ray reflectivity, AFM and optical reflectivity of 200-700 nm radiation indicate that the roughness of the silicon surface has enhanced substantially after ion irradiation. The diffusion of oxygen in silicon surface during ion irradiation is evident from the oscillation in the X-ray reflectivity spectrum and the sharp decrease in the reflectivity of 200-400 nm radiation. The rise in temperature, estimated from the heat spike model, was high enough to melt the local silicon surface. The results of XRD indicate that lattice defects have been induced and a new plane <2 1 1> has been formed in the silicon <1 0 0> after ion irradiation. The results of the present study show that the energy deposited in crystalline silicon through the process of electronic energy loss ∼0.944 keV/nm per ion is sufficient to induce disorders of appreciable magnitude in the silicon surface even at a fluence of ∼10 13 ions/cm 2 .

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“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. The mechanism for energy loss suffered by low energy ions in semiconductor, metal, etc.…”

Section: Introductionmentioning

confidence: 99%

Surface disorder in c-Si induced by swift heavy ions

Bogle

Gokhale

Bhoraskar

2005

Radiation Effects and Defects in Solids

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“…Though neutron should be the ideal source, material after neutron damage is often radioactive. An alternate have often sought through light ions (like proton or helium) [52,54] and heavy ions [39,41,50,52,63] damage. Equally important is the subject of damage (radiation) quantification.…”

Section: Introductionmentioning

confidence: 99%

“…This can be classified in terms of microstructural changes [24,28, and microstructural dependence [28,[60][61][62]. Radiation damage has been reported to enforce all possible structural changes: creation of vacancies/interstitials and dislocations [36][37][38][39][40][41][42][43][44][45], transmutation of alloying elements [46], dissolution and re-precipitation [47][48][49], amorphization [50][51][52], developments of stresses and lattice rotations [53], radiation-induced segregation (RIS) [54][55][56], voids and void swelling [57,58], etc. On the other hand, both alloy chemistry [21,[27][28][29] and crystallographic orientations [59][60][61] are known to affect the damage kinetics.…”

Section: Introductionmentioning

confidence: 99%

“…Equally important is the subject of damage (radiation) quantification. This has usually been attempted through either macroscopic [16,[23][24][25][26][27][28][29][31][32][33][34]40,42] or microscopic [16,[23][24][25][26][27][28][29][31][32][33][35][36][37][38][40][41][42][46][47][48][49][50][51][52] characterization: neglecting the in-between domain of mesoscopic measurements. Finally, the modelling of radiation damage appears equally challenging.…”

Section: Introductionmentioning

confidence: 99%

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Orientation sensitivity of focused ion beam damage in pure zirconium: direct experimental observations and molecular dynamics simulations

Revelly

Srinivasan

Panwar

et al. 2014

Philosophical Magazine

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A high-purity predominantly single crystalline zirconium was subjected to controlled focused ion beam (FIB) damage. Damage estimates were obtained from electron backscattered diffraction (EBSD) and nano-indentation measurements on exactly the same area/orientation. The damage kinetics, between different crystallographic orientations, differed by one order of magnitude and a clear hierarchy of orientation sensitive ion damage emerged. Use of a simple geometric approach, linear density of atoms and corresponding scattering cross-sections to impinging gallium ions, could differentiate between extreme damage kinetics; but failed when such differences were relatively minor. Numerically intensive molecular dynamics (MD) simulations, on the other hand, were more effective. However, MD simulations or direct EBSD observations failed to justify anisotropic irradiation hardening (AIH): 3-8 times more hardening for near basal. Though explanation for AIH is indirect, evidence and rationalization for orientation-sensitive radiation damage appears clear and statistically reproducible.

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“…Although many ion implantation studies in silicon have been reported in the literature during the last two decades, most of them could not be used for determining amorphization energies. They were either not well enough documented to extract reliable data for this type of analysis or were performed at room temperature, where thermal effects, which are already discernible at 210 K [6], [7], [8] and [9], significantly modify defect concentration. Transition of crystalline to amorphous silicon is believed to be due to the formation of di-vacancies and diinterstitials during ion implantation, which rearrange to generate the typical five-and seven-member rings observed in the amorphous state [9] and [10].…”

Section: Introductionmentioning

confidence: 99%