Self-Aligned Microfabrication of Metal-Semiconductor Contacts by Projection-Patterned Excimer Laser Doping

Self-aligned microfabrication of metal-semiconductor contacts by projection-patterned doping using a KrF excimer laser and SiH 4 gas is demonstrated. Copper thin films with a linewidth as narrow as 2.35 µm are deposited selectively on the doped region by electroplating using a CuSO 4 aqueous solution. In addition, Au thin films with a linewidth of 1.57 µm are also deposited selectively by electroless plating in an Au-24s aqueous solution. Various properties of the metal thin films deposited by the different plating conditions are discussed. Using the selective metallization process, nonalloyed ohmic contacts can be fabricated with a specific contact resistance as low as 4.95×10 -6 Ωcm 2 , which is 1/150 of that of the conventional alloyed contacts.