Revealing Laser Crystallization Mechanism of Silicon Thin Films via Pulsed IR Lasers

Pulsed laser absorption-mediated explosive crystallization of silicon films has extensively been studied using microscopy techniques on single laser pulse-irradiated regions in the literature. In this work, we experimentally demonstrate and theoretically explain in detail the use of slow quenching regime for laser crystallization mediated by highly overlapping pulses. Increasing the use of Si in thin film transistors and photovoltaic applications drives researchers to find cost-effective and efficient ways of manufacturing crystalline Si films on various types of substrates. Understanding the mechanism of the laser crystallization process of Si films by pulsed lasers becomes crucial. This work reveals the laser crystallization mechanism of Si thin films in macroscopic scales by considering heat transfer and accumulation dynamics. Our motivation is to describe the dynamics of the laser crystallization of Si films to provide a complementary guide for the production of device-grade c-Si films by infrared pulsed laser without employing preheated substrates. c-Si grains exceeding 2 mm in size were formed by laser crystallization of 1 μm-thick Si films without any pre/postannealing step at room temperature and within a typical continuous wave irradiation-based light energy budget, which we think to be the most important achievement of our work.