Ultra-Thin Silicon Wafers Fabrication and Inverted Pyramid Texturing Based on Cu-Catalyzed Chemical Etching

The ultra-thin silicon solar devices perform a potential development direction to decrease material usage and thus lowering the expense. The ultra-thin silicon wafer and inverted pyramid structure texturing were completed by one-step Cu-catalyzed chemical etching (CCCE). In this paper, the influence of H2O2 concentration, Cu (NO3)2 concentration, reaction temperature, and etching time on surface geometry, wafer thickness and light trapping were systematically investigated. The conclusion shows that introduce Cu-particles can significantly accelerate the dissolution of the silicon wafer, the thinning rate of 18 μm/min is more 40-times faster than that of conventional KOH thinning system. Inverted pyramid structure covered thin silicon wafer has ultra-low reflectivity of ~0.5% in the spectrum range of 300~1000 nm. The etching and inverted pyramid structure formation mechanism has finally discussed. The current work develops a new approach for thin silicon manufacturing. Which can be precisely managed by adjusting etching parameters that unlock potential applications in the microelectronics and solar cell market.