Electrical Activation of Boron in Si Film Using Excimer Laser Annealing

After UV (ultra-violet) pulsed ELA (excimer laser annealing) for highly-boron doped Si films, the conductivity and the correlated crystallinity in the film were evaluated by comparing them with the case of SPC (solid phase crystallization) in a furnace chamber at the temperature below 650 degrees C. The sheet resistance decreases drastically with improving crystallinity by performing ELA. By optimizing the ELA conditions, efficient solidified activation after melting occurs and the Si film with a 50 nm thickness shows an extremely low sheet resistance of 50 ohm/square at a dose of 5 x 10(15) cm(-2). The analytical result from the Hall measurement suggests that the drastic activation after ELA is due to the high carrier concentration, which relates to the higher crystallinity. ELA activation for heavily-impurity-incorporated Si films is effective not only for the formationof the source and the drain or the Si gate in CMOS (complementary metal oxide semiconductor) TFTs (thin-film transistors) but also for the electrode in pin photo-sensor diodes for SoP (system on panel) and solar cell applications.