Abstract: An optical method for controlling the thickness of a layer of material as it is deposited upon a substrate advanced through a glow discharge chamber. A source of radiant energy of white light, and a detector are so positioned that the energy of the source is reflected from the substrate to the detector. A control system accepts the output of the detector to generate control signals responsive to layer thickness for adjusting the deposition parameters of the chamber.

Abstract: Apparatus for developing a substantially uniform temperature distribution across the entire transverse width of a relatively thin, relatively large area substrate onto which a plurality of amorphous semiconductor layers will be deposited in a glow discharge deposition chamber. The apparatus includes a plurality of spaced heating elements, the filaments of which are suspended above and angled relative to the plane of the substrate so as to direct radiation onto that portion of the substrate which loses heat at the greatest rate with at least the same intensity as, and preferably greater intensity than, radiation is directed onto those portions of the substrate which lose heat at lesser rates. By establishing the greatest intensity of radiation adjacent that portion of the substrate which most readily loses heat, a uniform distribution of temperature across the transverse width of the substrate may be achieved.

Abstract: Apparatus for raising a continuous substrate to a predetermined deposition temperature and thereafter maintaining it at that temperature as it advances through a glow discharge chamber. A lamp holder having a plurality of heater lamps extends substantially the length of the chamber. The lamps are selectively spaced apart along the length of travel of said substrate to provide a desired heating profile. A detector is engaged to control circuitry for continuously adjusting the intensity of the lamps to regulate substrate temperature.