Title :
Directional solidification of 80 kg multicrystalline silicon ingots by HEM
Author :
Khattak, C.P. ; Schmid, F. ; Cunningham, Douglas W. ; Summers, J.G.
Author_Institution :
Crystal Systems Inc., Salem, MA, USA
Abstract :
The heat exchanger method (HEM) has been utilized to produce multicrystalline silicon ingots of 44 cm square cross-section weighing 80 kg. Controlled solidification of these ingots has been achieved at the rate of ~10 kg/h with a total cycle time of 48 h. Large grains of 1 to 2 cm size with columnar, vertically oriented grain boundaries are produced. The resistivity within the ingot has been maintained in a narrow range (±0.3 Ω-cm). Diffusion lengths of 150 μm have been measured on the wafers from the bulk of the material. The process is being utilized in production for photovoltaic applications
Keywords :
directional solidification; elemental semiconductors; grain boundaries; heat exchangers; semiconductor growth; semiconductor technology; silicon; 1 to 2 cm; 44 cm; 48 h; 80 kg; cycle time; diffusion lengths; directional solidification; heat exchanger method; multicrystalline Si ingots; photovoltaic applications; resistivity; semiconductors; vertically oriented grain boundaries; Costs; Crystallization; Furnaces; Grain boundaries; Insulation; Photovoltaic systems; Production; Silicon compounds; Solar power generation; Throughput;
Conference_Titel :
Photovoltaic Specialists Conference, 1991., Conference Record of the Twenty Second IEEE
Conference_Location :
Las Vegas, NV
Print_ISBN :
0-87942-636-5
DOI :
10.1109/PVSC.1991.169354
