Surface passivation of crystalline silicon solar cells: a review

Abstract

In the 1980s, advances in the passivation of both cell surfaces led to the first crystalline silicon solar cells with conversion efficiencies above 20%. With today's industry trend towards thinner wafers and higher cell efficiency, the passivation of the front and rear surfaces is now also becoming vitally important for commercial silicon cells. This paper presents a review of the surface passivation methods used since the 1970s, both on laboratory‐type as well as industrial cells. Given the trend towards lower‐cost (but also lower‐quality) Si materials such as block‐cast multicrystalline Si, ribbon Si or thin‐film polycrystalline Si, the most promising surface passivation methods identified to date are the fabrication of a p–n junction and the subsequent passivation of the resulting silicon surface with plasma silicon nitride as this material, besides reducing surface recombination and reflection losses, additionally provides a very efficient passivation of bulk defects. Copyright © 2000 John Wiley & Sons, Ltd.

Influence of annealing and Al2O3 properties on the hydrogen-induced passivation of the Si/SiO2 interface

“…In addition, we verified (on different type of wafers) that the passivation performance of the stack was similar to that obtained after "alnealing" (annealing the SiO 2 with a sacrificial Al-layer), which is known to lead to an excellent passivation quality. 18,34,35 It was, furthermore, found that annealing in N 2 led to the same passivation performance for the stacks as annealing in forming gas. The observation that the shape of the effective lifetime curves is the same for forming-gas annealed SiO 2 and SiO 2 /Al 2 O 3 stacks is in accordance with a similar prevailing mechanism underlying the passivation properties, i.e., a high level of chemical passivation.…”

Studies on the structural properties of SiO:H films prepared from (SiH4+CO2+He) plasma in RF-PECVD

“…It has been known for years that a-SiO:H exhibits visible photoluminescence [1][2][3] and has been applied in the p-i-n junction light-emitting diode [4]. In conventional c-Si solar cells, a-SiO:H has already been used as surface passivation layer [5]. Being a wide-optical-gap material it has important application as window layer in multi-junction solar cells [6,7].…”

Feasibility of Antireflection and Passivation Coatings by Atmospheric Pressure PECVD

“…The usual process to obtain antireflection and passivation coatings on p-type silicon solar cells is the growth of hydrogenated silicon nitride (SiN x :H) films by low pressure plasma-enhanced chemical vapor deposition (LP-PECVD) using silane (SiH 4 ) and ammoniac (NH 3 ) as gas precursors [3]. The major advantage of SiN x :H films is that they provide both an efficient front surface passivation and have an adequate antireflective behavior [4,5].…”