Gold diffusion method for semiconductor devices of high switching speed

摘要

Gold is diffused into a silicon substrate by first depositing an ultrathin layer of gold on one of the main faces of the substrate and then by heating the substrate to a temperature range of about 300 DEG -850 DEG C., instead of to about 1000 DEG according to the prior art. Then, following the removal of the remaining gold layer from over the substrate, the latter is reheated to a higher temperature ranging from about 700 DEG C. to about 1000 DEG C. for activating the diffused gold. The gold diffusion at the reduced temperature serves to decrease the surface irregularities of the substrate as a result of gold-silicon alloy zones created at the interface between gold layer and silicon substrate during the thermal diffusion process.