Thin metal films deposited at low temperature for optoelectronic device application

Thin metal layers play an important role in the development of electronic devices. Thin metal films deposited at low temperature (LT=77 K) have shown some unique properties which enhance device performance. The microstructure properties of thin metal films formed at room temperature (RT=300 K) and LT were investigated in this work. An insulating substrate was used for Au, Ag, and Al metal deposition. The surface morphology and microstructure of the metal films was studied by transmission electron spectroscopy (TEM) and atomic force microscopy (AFM). The resistance of the thin films was measured in situ as a function of film thickness and temperature. It was found that all LT thin films become electrically continuous at a much lower thickness than the RT films. Electrical measurements determined that the LT films demonstrated several orders of lower resistance compared to RT film at very thin (less than 100 Angstrom) thickness, which could lead to the potential applications of these films on electronic and optoelectronic devices. It is observed by both TEM and AFM that the LT films showed much lower density of grain boundaries than the RT samples at the same thickness. This is consistent with the resistance measurement results. (C) 1996 American Vacuum Society.