Surface Modifications by Swift Heavy-Ion Irradiation of Indium Phosphide

Abstract

InP (001) samples were irradiated with 200 MeV Au ions at different fluences. The surface nanotopographical changes due to increasing fluence of swift heavy ions were observed by Atomic Force Microscopy (AFM), where the onset of a large increase in surface roughness for fluences sufficient to cause complete surface amorphization was observed. Transmission Electron Microscopy (TEM) was used to observe bulk-ion tracks that formed in InP, and high resolution TEM (HRTEM) revealed that single-ion tracks might not be amorphous in nature. Surface-ion tracks were observed by AFM in the form of ill-defined pits (hollows) of ∼12 nm in diameter (width). In addition, Rutherford backscattering was utilized to follow the formation of disorder to amorphization in the irradiated material. The interpretation of the large increase in surface roughness with the onset of amorphization can be attributed to the plastic phenomena induced by the change of states from crystalline to amorphous by ion irradiation.