35.1: Blue‐Diode Laser Annealing of Amorphous Silicon Films for Low‐Cost, Large‐Scale Manufacturing of Advanced Displays

Abstract

Blue diode laser annealing (BLA) systems have been successfully developed for low‐temperature crystallization from amorphous silicon film on glass substrates. It is demonstrated that it can achieve high quality poly‐Si film with large grain sizes, as studied by optical microscopy, Raman spectroscopy and AFM measurements. The p‐channel poly‐Si TFT on glass using BLA exhibited the field‐effect mobility of 168.05 cm2/Vs and subthreshold swing of 220 mV/dec. BLA is scalable to large‐scale display manufacturing and significantly lowers the capital expense and operating cost, since diode lasers are highly reliable and rugged, remarkably efficient, and maintenance‐free, allowing 24/7 operations without the need of consumables. The BLA system consists of an array of high‐power blue diode lasers (λ ~ 450 nm) and beam‐shaping optics to produce a line‐shaped beam which can be scanned at high speed to anneal the Si film in a single scan, where the high scan speed minimizes thermal stress. The scan‐to‐scan is seamless to cover a large panel such as G6 or G8 without glass damage. The physical phenomena responsible for melting and recrystallization are explained by heat transfer simulations for process optimization.

9‐1: Fabrication of Lateral Crystal Si on Cu Bottom‐Gate Structure via Blue‐Laser Diode Annealing (BLDA)

“…Continuous wave (CW) laser annealing is capable to fabricate large grain size Si as like lateral and single crystal [2][3][4][5][6]. Such large crystal significantly improve TFT mobility and have high uniformity.…”