A high efficiency industrial polysilicon solar cell with a honeycomb-like surface fabricated by wet etching using a photoresist mask

Abstract

In this paper, an effective and low cost method of texturization was introduced into the fabrication process for industrial multicrystalline silicon solar cell production. The purpose of the method was to reduce reflectance by creating a honeycomb-like textured surface using a masked wet etching process. A negative photoresist film was selected as an etching mask. Although large surface roughness of wafer was considered to affect the adhesion and acid resistance of etching mask, a honeycomb-like textured surface with a pitch of 18μm was fabricated successfully. The etched pits had a nearly smooth spherical segment surface, an average aperture of 15.1μm, and a depth of 6.5μm. This regular textured surface had a low light reflectivity of approximately 20.5% and greatly increased the carrier lifetime. Compared with multicrystalline silicon solar cells textured by conventional acid etching, the average short circuit current increased by 2.2% and the average efficiency increased from 17.41% to 17.75%, a net gain of 0.34%. And a high throughput above 2400 pieces per hour was obtained. This texturing technique is expected to promote the application of diamond-wire cut multicrystalline silicon wafers with the low saw-damage in the future.