Rear side passivation of PERC‐type solar cells by wet oxides grown from purified steam

Abstract

To considerably improve the conversion efficiency of industrial solar cells, the effective passivation of the rear surface is a prerequisite. Thermal grown silicon oxides provide an excellent level of surface passivation on lowly doped p-type surfaces. However, dry thermal oxidation processes require relatively high temperatures (?1000°C) and, due to the low growth rate, long process times. To decrease both oxidation temperature and process time, the dry oxidation process can be replaced by a wet oxidation. The most common way to introduce high purity water vapor into the oxidation tube is the pyrolytic generation from high purity gases (H2 and O2). A more easy and cost effective option for the supply of water vapor that was applied within this work is the direct purification of steam. The passivation quality of dry and wet oxides, the latter grown from pyrolytic generated water vapor and purified steam was compared within this work. The passivation quality obtained for the wet oxides grown from purified steam was found to be comparable to those oxides grown from pyrolytic generated water vapor. On laser fired contacts (LFC) solar cells conversion efficiencies well above 20% could be achieved independent of the oxide that was applied for the rear side passivation

High-efficiency Silicon Heterojunction Solar Cells: A Review

“…Here, it is motivated rather by the (too) high processing temperatures such oxides require [9]. Wet-thermal oxides are grown at lower temperatures [10], and have proven their use in solar cells [11,12]. Other PV-suitable dielectrics include amorphous siliconnitride (a-SiN x :H) [13,14], SiO 2 /a-SiN x :H stacks [9,15], or aluminum-oxide (Al 2 O 3 / films [16][17][18].…”

A Review on Silicon Oxide Sureface Passivation for High Efficiency Crystalline Silicon Solar Cell

“…Thermal oxidation 방법으로 성장시킨 실리콘 산 화막과 결정질 실리콘 사이의 훌륭한 계면 특성은 태 양전지의 높은 효율을 가져온다 [6,7]. Thermal SiO 2 는 열처리 후 낮은 SRV 특성을 가진다 [7][8][9].…”

Photo‐Electrical Characterization of Silicon Micropillar Arrays with Radial p/n Junctions Containing Passivation and Anti‐Reflection Coatings

“…These fuels, which can be sustainably produced in liquid or gaseous form, may offer several benefits, such as wileyonlinelibrary.com the efficiency of Si micropillar PV cells by applying a passivation and anti-reflection (AR) coating. We will discuss the deposition and in-depth characterization of various surface coatings (aluminum oxide (Al 2 O 3 ), [10,14,15] silicon-rich silicon nitride (SiN x ), [16] silicon dioxide (SiO 2 ), [14,17] and indium-doped tin oxide (ITO) [18] ) on Si micropillar arrays with a radial p/n junction, to function as a passivation, anti-reflective, and possibly also as a conductive layer. In order to function as an AR coating, the thickness has to be optimized separately for each material.…”