Abstract: An amorphous semiconductor film is prepared by the usual procedure and, then, established by exposing it to sufficient light intermittently to age the same. The degradation of the electrical characteristics of the semiconductor film on prolonged exposure to light is minimized by the above technique. The preferred intermittent light is a pulsed light. The above light treatment may be applied to an individual semiconductor film, a laminated assembly including at least the pin layers, a finished semiconductor device such as a solar cell or a semiconductor device prior to attachment of an electrode.

Abstract: 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.degree.-850.degree. C., instead of to about 1000.degree. 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.degree. C. to about 1000.degree. 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.