Crystalline silicon plate or strip prodn. with columnar structure - suitable for making large solar cell by sintering on reusable quartz substrate

摘要

Prodn. of crystalline Si plate or strip with columnar structure, esp. suitable for making solar cells of large area, 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 DE2927086. Improvement is that crystalline or granular quartz in the form of quartz material or sand is used as the sintering substrate. Pref. the substrate consists of a (1-2 mm thick) layer of quartz, which has been pressed smooth, or a (0.2-0.5 mm thick) quartz engobe on an A1203 support. The quartz is over 99.9% pure. After sintering, any quartz sand adhering to the Si pt. is removed, pref. by sand blasting. Substrate can be used for further sintering processes and its long life improves the economy of the process.