Mfg. crystalline silicon sheet or strip with columnar structure - suitable for making large solar cell, by sintering and brief pulsed surface heating

摘要

Prodn. involves making a slip from Si powder with a particle size of under 1 micron and a binder, spreading the slip on a substrate and drying the sheet formed, then removing the substrate and sintering the sheet below 1400 deg.C on an inert, refractory substrate in a protective gas atmos. until a layer of monocrystalline granules of dia. corresp. to the thickness of the sheet is obtd. as in 2927086. The novel feature is that, during sintering, short heat ray(s) are directed downwards onto the plane Si sheet on the sintering substrate, the heating pulse duration being adjusted so that the Si sheet melts briefly in the thin surface layer. Max grain growth is obtd. without reaction with the substrate.