Hydrogen plasma etching technique for mono- and multi-crystal line silicon wafers

A new etching technique for crystalline silicon wafers is developed. The etching technique uses hydrogen radicals supplied by hydrogen remote plasma at room temperature with gas pressures of 0.2-0.5 Torr and hydrogen flow rates of 160-180 sccm for 5-60 min. Scanning electron microscope (SEM) images are used to investigate the surface morphology after etching process. Furthermore, the surface reflectances of the etched samples are measured to estimate the optical properties of the etched samples. An excellent optical properties of the etched surfaces are found where low surface reflectance below 2% are realized at the wavelength regions between 500-900nm. In addition, the technique is applied to chemically textured crystalline silicon wafers to investigate the technique ability of further improving the already textured surfaces. The results show that hydrogen plasma etching technique is very effective to reduce the surface reflectance properties of surfaces textured with alkaline solutions. Furthermore, possibility of applying this technique to multicrystalline silicon wafers has been investigated. The primary results show a small reduction in surface reflectance as for samples etched with hydrogen flow rates of 170 sccrn and 180 sccm.