SOLUXOR - SOLAR Wafer
We currently offer multi-crystalline and mono-crystalline wafers in principal sizes of 156*156 mm and 125*125 mm, with thicknesses from 180 to 220 microns. Strategic relationships with world class PV equipment manufacturers GT Solar (USA) HCT (Switzerland), support SOLUXOR on equipment, process and technology. Technological innovations and improvements in processing technologies have enabled us to progressively reduce silicon consumption and improve the quality of our wafers.
The following flowchart shows the manufacturing process of our solar wafers
Ingot Production
High purity solar-grade virgin multi-crystalline silicon is loaded into a quartz crucible for melting in a furnace. The molten multi-crystalline silicon forms a single solid crystal rod as it cools and is pulled from the crucible by a puller using a rotating upward motion in a vacuum chamber. The size of the ingot is determined by the size of the wafer that it will be used to produce, with 125*125 mm wafers being produced from ingots that are approximately 150*165 mm in diameter and 156*156 mm wafers being produced from ingots that are 156*156mm in width and length. Finished ingots are tested for resistivity, lifetime and other specifications before they are processed for wafer.
The scraps which are generated in mono-crystalline silicon wafer production and no longer useful for mono-crystalline silicon wafers can still be used for multi-crystalline silicon wafer production and the scraps generated in multi-crystalline silicon wafer production can be purified by mono-crystalline silicon furnaces to be usable again in multi-crystalline silicon wafer productions. Such an internal recycling from the balance mono/multi strategy results in feed augmentation and cost savings.
Wafer
Each silicon ingot is cropped and squared using sophisticated cropping saws and squares before they are sliced into wafers. The corners of square ingots are grinded before slicing. We are currently using 120 micron wires for slicing the squared ingots into wafers, the process of replacing such 120 micron wires with 100 micron wires are tested, as the use of thinner wires cause less multi-crystalline silicon wastes in the slicing process. We are currently capable of slicing wafers with a thickness of approximately 170 microns, which allows us to enjoy higher production yields.
Multi-crystalline Silicon Wafer
Compared with mono-crystalline silicon wafers, multi-crystalline silicon wafers have a comparatively less stringent requirement on raw material purity and the process of manufacturing multi-crystalline silicon wafers is simpler. Therefore multi-crystalline wafer is widely used in solar industry to produce solar cell. SOLUXOR currently provides the multi-crystalline wafers of specification 156mm by 156 mm with thickness 200 microns
Mono-crystalline Silicon Wafer
Compared with multi-crystalline silicon wafers, mono-crystalline silicon wafers need high purity raw material and the manufacturing process of mono-crystalline silicon wafer is comparatively more complicated, so the price of mono-crystalline silicon wafer is higher. But the conversion efficiency of mono-crystalline silicon wafer is higher, so using mono-crystalline silicon cells instead of multi-crystalline silicon cells can save area. SOLUXOR currently provides the mono-crystalline silicon wafers of specification 125mm by 125 mm with thickness 200 microns