1337465 Coating with glass MATSUSHITA ELECTRONICS CORP 28 Sept 1971 [29 Sept 1970] 45147/71 Heading C1M [Also in Division H1] A target for an image pick-up tube comprising a silicon substrate 31, Fig. 3, coated with a layer of silicon dioxide 34A provided with apertures through which P-type areas 33 are exposed is coated with a layer of lead silicate glass 34B and 34E formed by the combination of lead monoxide with the silicon or silicon dioxide surface. The lead silicate glass layer should have a specific resistance of 10<SP>8</SP>-10<SP>12</SP> ohm-cm. and a thickness of 0À1-0À5 microns. In manufacture the silicon wafer is provided with the oxide layer and the P-type areas in known manner and lead is vapour deposited over this surface; heating at 450-650‹ C. in an oxidizing atmosphere converts the lead to lead monoxide which reacts with the surface to form lead silicate glass. Surplus lead monoxide remaining after the above process is removed by washing in acetic acid. As an alternative the lead monoxide layer can be formed directly by vapour deposition. The lead glass film 34E over the junction areas may be removed since it adds resistance to the path of the electron beam.
