A Polycrystalline Silicon Thin-Film Transistor With Self-Aligned Metal Electrodes Formed Using Aluminum-Induced Crystallization

A low-temperature technology for the fabrication of a polycrystalline silicon (poly-Si) thin-film transistor (TFT) with self-aligned metal electrodes (SAMEs) is demonstrated. The conventional poly-Si source and drain regions are amorphized by self-aligned dopant implantation before they are replaced by aluminum via an aluminum-induced crystallization (AIC) process. AIC is selective between amorphous and poly-Si. No deliberate dopant activation process is needed, and the field-effect polarity of a SAME poly-Si TFT is determined by that of the dopant used for the amorphization. SAME poly-Si TFTs with channel lengths down to 1 have been realized. The effects of aluminum thickness on AIC and those of the AIC annealing temperature and time on the performance of a SAME poly-Si TFT are also reported.