Method of manufacturing a semiconductor device in which a semiconductor zone is formed through diffusion from a strip of polycrystalline silicon

A method of manufacturing a semiconductor device whereby on a surface (3) of a semiconductor body (1) a conductor track (21) of polycrystalline silicon insulated from the surface (3) is provided in a layer of doped polycrystalline silicon (11) provided on a layer of insulating material (10), and whereby a strip of polycrystalline silicon (19, 35) is formed between an edge (18) of the conductor (21) and a portion (24, 34) of the surface (3) adjoining the edge (18), after which a semiconductor zone (30) is formed through diffusion of dopant from the conductor (21) through the strip (19, 35) into the semiconductor body (1). During the formation of the insulated conductor (21) and the strip of polycrystalline silicon (19, 35), a window (15) is etched into the layer of polycrystalline silicon (11) by means of a first etching mask (13), after which the insulating layer (10) is removed from the surface (3) within the window (15), the window (15) is provided at its edge (18) with a strip of polycrystalline silicon (19, 35), and the conductor (21) is etched into the layer of polycrystalline silicon (11) by means of a second etching mask (20), this second etching mask (20) covering at least a portion of the edge (18) of the window (15). Further conductors (22, 23) may be formed in the polycrystalline layer (11) next to the insulated conductor (21), all conductors (21, 22, 23) being given dimensions such as defined by the second etching mask (20).