United States Patent ( 19 ) Mizushima et al . 54 ) DOPING FROM A PHOTORESIST LAYER

A method for fabricating semiconductor devices com prising the steps of forming on the main surface of a semiconductor substrate an inorganic photoresist layer having a first amorphous layer, which contains Seas a matrix component and includes an impurity for provid ing one conductivity type and a second silver, or a silver containing layer, formed on the first layer; expos ing the inorganic photoresist layer with an exposure pattern; developing the exposed inorganic photoresist layer to form a patterned impurity containing inorganic photoresist layer as an impurity source layer; forming a heat resistive overcoating layer on the main surface of the semiconductor substrate, while covering the impu rity source layer; and forming a doped region by diffus ing impurity from the impurity source layer into a re gion of the substrate underlying the impurity source layer. The heat resistive overcoating layer may be an insulation layer having a window through which a conductive layer is connected to the doped region and is extended over the overcoating layer. The doped re gion is formed readily and accurately with relatively few process steps and with a pattern corresponding to an exposure pattern for the inorganic photoresist layer. The diffusion of the impurity from the impurity source layer into the substrate is accurately controlled so as to provide the doped region with a desired impurity con centration. Moreover, the evaporation of the impurity into the atmosphere during processing is minimized.