Investigations on the Effects of 150 MeV Ag Ion Irradiations on 4H–SiC

Abstract

Investigations have been carried out on the morphological and the optical properties of 4H–Silicon Carbide (SiC) wafers after the 150 meV Ag ion irradiation for the fluences 5E10,1E11, 5E11, 1E12, 5E12 and 1E13 ions/cm². The SRIM calculations show that the penetration depth of Ag ions is ~11.90 μm and the electronic energy loss (S_e) is dominant compared to the nuclear loss energy (S_n) and the modifications are due to S_e. The images from atomic force microscopy (AFM) show the formation of Quantum Dot (QD) like nano-structures at low fluences which develop into triangular island like structures with increasing the ion fluence. The surface roughness of the sample increases after the irradiation due to the formation of triangular islands. Raman spectra show change in the intensity of the standard modes of 4H–SiC with a shift in the E₂ (TO) mode. At the fluence of 5E10 ions/cm², there is a formation of a shoulder in A₁ (LO) optical mode which disappears as the fluence increases. The Raman mapping of the samples show that the irradiation is uniform.