Silicon https://doi.org/10.1007/s12633-018-9882-4 ORIGINAL PAPER Amorphization of SiO 2 Thin Films by Using 200 MeV Ag 15+ Ions Anil Gaikwad 1 · Yogesh Mhaisagar 1 · Swati Gupta 1 · Bhavana Joshi 2 · Kandasami Asokan 3 · Ashok Mahajan 1 Received: 22 January 2016 / Accepted: 23 April 2018 © Springer Science+Business Media B.V., part of Springer Nature 2018 Abstract Effect of swift heavy ions (SHI) on low-k SiO 2 thin films has been investigated. SiO 2 thin films were deposited on pre- cleaned p-Si substrate by using sol-gel spin coating technique. Further, deposited films were annealed at 400 ◦ C to remove structural irregularities. Prepared samples were irradiated with 200 MeV Ag 15+ ions at different ion fluence such as 5 ×10 11 , 1 × 10 12 and 5 × 10 12 ions/cm 2 . Deposition of SiO 2 was confirmed by using EDAX and FTIR spectroscopy. Increase in ion fluence increases the RMS roughness from 1.49 to 7.79 nm. The transformation of deposited material from polycrystalline to amorphous nature was confirmed from XRD spectra. Increase in SHI fluence decreases the grain size from 181.3 to 74.1 nm for pristine and sample irradiated at 5 × 10 11 ions/cm 2 . Whereas, for sample irradiated with 5 × 10 11 ions/cm 2 fluence doesn’t show crystalline peak at (011). It is observed that SHI irradiation leads to grain agglomeration with decrease in crystal size at higher fluence. Further, conductivity of the samples under study was observed to be decreased with increase in ion fluence. Thus, it is demonstrated that the surface and structural properties of low-k silica thin films can be tailored by controlling the SHI fluence. Keywords Thin film · Irradiation · Amorphization · AFM · Sol-gel 1 Introduction Now a days people are planning for extra-terrestrial civilization, such missions are strongly supported by semiconductor industry [1, 2]. The materials used to fabricate such devices play vital role in the functioning of devices for space applications [3–7]. These devices are continuously exposed to radiations available in space. Radiations in space can have deep impact on properties of material. This leads to reliability issues and failure mechanism of the devices. Silica has often subjected to ion irradiation in industrial fabrication processes and in space applications by cosmic rays, therefore it is interesting to study the effect of amorphization on SiO 2 due to radiations.  Ashok Mahajan ammahajan@nmu.ac.in 1 Department of Electronics, North Maharashtra University, Jalgaon 425 001, M.S. India 2 Department of Mechanical Engineering, Korea University, Seoul, 136-713, Korea 3 Inter University Accelerator Center, Aruna Asaf Ali Marg, New Delhi 110 067, India The radiations available in space are continuously attacking on the device material, this interaction will cause damages or it can degrade the device performance. Hence, study of effect of swift heavy ions (SHI) on material properties of devices used in space applications has attracted more attention. In particular, SHIs are a fast heavy ions with energy ∼ MeV/amu. SHI penetrates deep into the materials and while passing through the materials losses its energy in the material per unit length and it is called stopping power (S). There are two types of stopping powers namely electronic stopping (S e ) and nuclear stopping (S n ) [8]. High energy bombardment of SHIs gives rise to change in the physical properties of the material. SHI irradiation has been used to create defects and to anneal the defects [9]. The degree of disorder can range from point defects to a continuous amorphous zone along the ion path [10]. The previous investigations allowed the establishment that, the electronic energy loss released by the SHI ions can create atomic level rearrangements in various types of materials [11]. SHI has proven application for the modification of SiO 2 films viz., ion tracks formation [12– 14], phase separation [15], formation of color centers [16, 17], refractive index tuning [18], lattice distortion [19], enhancement in photoluminescence reactivity [20– 22], phase transformations [23–31] etc. The heavy ion