| 摘要 |
1536900 Semiconductor device manufacture MOBIL TYCO SOLAR ENERGY CORP 15 Oct 1976 [5 Dec 1975] 42956/76 Heading H1K A tube of substantially monocrystalline (as defined in the Specification) semiconductor or insulating material of generally elongate crosssection, opposed portions of which are flat or much less curved than the intervening edge portions, is produced and the edge portions of the tube severed to separate the flat or less curved portions. Though the tube may be of sapphire it is preferably a flat-sided tube of silicon grown by the edge-defined film-fed growth technique described in United States Specifications 3,591,348 and 3,687,633 using the graphite die assembly of Fig. 1 (not shown). Its edges may be severed with a diamond cutter or preferably by etching along edge-adjacent lines exposed through a positive photoresist mask. Solar cells may be fabricated by forming a PN junction either in the tube or in the severed flat portions by diffusion, ion-implantation or epitaxy. In a preferred method phosphorus is diffused from its oxychloride in oxygen into both faces of a portion of P type silicon to provide an NPN structure, one N layer of which is subsequently removed by etching. Electrodes e.g. of electroless plated nickel or evaporated superposed layers of silver and aluminium are provided on opposed faces of the resulting structure, that on the light receiving N face being of grid form. Further subdivision of the severed flat portions into convenient sized pieces is envisaged. |
