13th International Conference on Fracture June 16–21, 2013, Beijing, China -1- Study on Radiation induced Mechanical Degradation of Amorphous Silicon Carbide Films Bo Meng1, Wei Tang1, Xuhua Peng1, Haixia Zhang1,* 1 Institute of Microelectronics, Peking University, 100871, CHINA * Corresponding author: hxzhang@pku.edu.cn Abstract In this paper, the radiation effects of 1MeV protons on hydrogenated amorphous SiC films are studied by simulation and experiments. The molecular dynamics simulation by SRIM-2012 software package indicates that compared to crystalline SiC, hydrogenated amorphous SiC may suffer less radiation damage. SiC films with a thickness of 500nm are deposited on silicon substrates by PECVD, and then annealed at about 450°C. The prepared hydrogenated amorphous SiC films are irradiated by 1MeV protons in an electrostatic tandem accelerator at a flux of about 1.4×1012 cm-2·s-1 for 2 hours. The mechanical changes in irradiated silicon carbide films are investigated by nano-indentation and nano-scratch method. The irradiated film suffers a decrease in hardness and Young Modulus, but keeps nearly the same friction coefficient and surface topography as the contrast films. Keywords Silicon Carbide, Mechanical degradation, Radiation damage 1. Introduction Silicon carbide was considered as an excellent candidate for Micro-Electro-Mechanical Systems, especially in harsh environments applications [1]. Compared to crystalline SiC, low-stress PECVD SiC thin film is more attractive for CMOS compatible MEMS structures and devices [2]. As with space applications, MEMS devices are working in a complex radiation environment with massive energetic particles and photons. Space radiation induces electrical and mechanical degradation in materials. MEMS structures and devices would suffer mechanical failures and electrical failures after large doses of radiation [3,4]. In recent researches, the radiation effects on crystalline SiC were studied. Microstructural, electrical, mechanical degradation and amorphization of crystalline SiC under ion and neutron irradiation were reported [5–7]. In this work, we focus on the radiation effects of 1MeV protons on amorphous SiC films. SRIM-2012 software package is used to calculate the ions distribution in multiple layers of SiC/Si target. PECVD SiC films are deposited and annealed. The prepared SiC films are irradiated by 1MeV protons at a flux of about 1.4×1012 cm-2·s-1 for 2 hours. The radiation induced mechanical degradations are investigated by nano-indentation and nano-scratch method. 2. Simulation SRIM-2012 software package, which concerns the stopping and range of ions in matter [8], is used to calculate the ions distribution in SiC and SiC/Si target. Table 1. The projected range of crystalline SiC and H-SiC. Samples Atoms(%) Projected Range (um) Si C H SiC 50 50 14.95 H-SiC 43 47 10 16.39 Since amorphous SiC films grown by PECVD generally contain a large number of hydrogen atoms, the projected ranges of 1MeV protons in crystalline SiC and hydrogenated amorphous SiC (H-SiC)
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