For solar wafers, poly-Si models will remain competitive over the next five years by using black silicon technology to hike energy conversion rates as well as enlarged crystal-growing furnaces and diamond saws to reduce wafer production cost, according to CTO Won Yao-peng for China-based solar wafer maker GCL-Poly Energy Holdings.

 

Energy conversion rates for poly-Si solar wafers have been hiked through improving crystal structure for 4-5 years but will be hiked in the future by virtue of black silicon technology to improve texturing, Won said.

 

RIE (reactive ion etching) dry etching and MCCE (metal-catalyzed chemical etching) wet etching are two processes based on black silicon technology, with the former able to increase energy conversion rates by 0.4-0.6pp and the latter by 0.2-0.4pp, Won indicated.

 

With enlargement in size of crystalline silicon ingots and sliced wafers, production cost can be reduced by 17% when crystal-growing is moved from G5 to G6 furnaces, and by 12% from G6 to G7, Won noted. The reduction in production cost between G6 and G5 is larger than that between G7 and G6 because part of slicing equipment has to be changed if G7 furnaces replace G6 ones, Won said.

 

In addition, adoption of diamond saws to slice ingots into wafers can decrease overall production cost due to lower slicing cost than traditional methods, Won indicated.

 

GCL-Poly Energy will extend production to mono-Si solar wafers through setting up annual capacity of 1GWp, with production to begin in the second quarter of 2016.