KOH-ETCH Related Defects on Processed Silicon Wafers

Abstract

KOH, an anisotropic etchant of monocrystalline Si, may cause roughness and defects whose shapes are related to crystallographic orientations. This paper studies the effect of processing steps on the formation of geometric etch defects. Implantation, thermal treatment, epitaxial growth or photoresist were not the source of such defects. In the scope of this study, only unwanted damage caused geometric etch defects. This makes the observation of the wafer after KOH etch a good indicator of the quality of previous steps.

Atomic force microscopy analysis of alkali textured silicon substrates for solar cell applications

“…It is often achieved by using anisotropy etching to modify the surfaces of (100) silicon substrates into square-based pyramidal structures [12]. Potassium hydroxide (KOH) and isopropyl alcohol (IPA) are the most preferred alkaline solutions used for anisotropic etching of silicon substrates [13][14][15][16][17][18][19][20][21]. Furthermore, the surface texturing of (100)-oriented silicon substrates can be used to improve the absorbance characteristics of silicon substrates [6], [21].…”