MICROFABRICATION OF SEMICONDUCTORS BY MEANS OF EXCIMER-LASER DOPING

Direct formation of three-dimensional structures of Si in GaAs by exci mer laser doping has been demonstrated. By using a thin solid Si dopan t source, linewidths as narrow as 0.3 mum are achieved. On the other h and, linewidths of 0.76 mum are obtained by projection-patterned dopin g in SiH4 gas atmosphere. The linewidth of the doped regions are discu ssed in relation to the lateral profiles of the calculated transient t emperature rise of the substrates. The patterned doping technique is a pplied to the selective metallization of GaAs. Au thin films are depos ited selectively on the doped regions by the subsequent electroless pl ating process. Using the selective metallization process, non-alloyed ohmic contracts can be fabricated with a specific contact resistance a s low as 4.95 X 10(-6) OMEGA CM2, which is 1/150 of that of the conven tionally alloyed contacts.