| 摘要 |
A polycrystalline film formed on a polycrystalline refractory substrate by vapour deposition is recrystallized (see Division B1) to form a plurality of large single crystals separated by grain boundaries. Further silicon may then be deposited to build up the monocrystalline structure. The substrate may be of alumina, graphite, magnesia, silicon carbide, zinc oxide, or titania. P-type doping may be effected during vapour deposition, after which an N-type dopant may be diffused into the upper surface of the layer to produce a P-N junction.ALSO:A silicon film comprising a plurality of large single crystals separated by grain boundaries is formed on a polycrystalline refractory substrate by depositing a polycrystalline silicon film from vapour on the substrate, heating the film over at least a portion of its area to a temperature 5-30 DEG C. above its mp (which is insuffient to form globules), and cooling the molten film 20-100 DEG C. to a temperature below its mp in 10-15 sec. After solidification, cooling to ambient temperature may be effected in 15-20 min. Heating may be effected progressively from one edge towards the opposite edge which may be left unmelted and from which the cooling may be commenced. The single crystal may have a length of 3,000 m , a width of 500 m , and a thickness of 10-20 m . The substrate may be of alumina, graphite, magnesia, silicon carbide, zinc oxide, or titania. Doping with boron or phosphorus may be effected during vapour deposition. |
