Overcoming current limitations of silicon thin film technology for flexible electronics

The phase of next generation electronic devices including display and photovoltaic are shifting toward flexible which needs low temperature process on the plastic films. However most of thin film technologies hardly avoid the high temperature process to achieve high quality. In this paper, we introduce a novel low temperature deposition process for nano-crystalline Si thin film, developed with the neutral particle beam (NB) technology. By our NB assisted CVD system (NBaCVD), the properly energetic particles can induce crystalline phase in Si thin films and effectively combine with heating effect on substrate. At low deposition temperature under 70°C, the NB with optimized incident energy effectively enhances the nano-crystalline formation in Si thin film. During the deposition process, energetic hydrogen-neutral atoms transport their kinetic energy to the surface of depositing film and enhance the crystal volume fraction (X_c) up to 80%, even though lower hydrogen dilution ratio (R<;30) and near room temperature. The electrical properties of Si thin films were varied from amorphous to nano-crystalline phase according to change of NB energies. The low temperature NBaCVD processed nc-Si TFTs (active layer 70°C, gate insulator 100°C) showed excellent performances as high mobility (~1.5 cm²/Vs), high stability (Vth shift <; 0.65 V under Vg=40 V, Vd=30V with light soaking condition) and high on/off ratio (~10⁶), and demonstrated their remarkable potentials for the TFT backplane of flexible AMOLEDs.