Surface and bulk passivation of multicrystalline silicon solar cells by ...

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2.2 Processing of Silicon Nitride Films for Si Solar Cells
Currently hydrogen containing silicon nitride (SiΝ :H) layers deposited by plasma
enhanced chemical vapor deposition (PECVD) method have been extensively employed
as AR coatings for multicrystalline Si solar cells. This is because of its capability to
accomplish multiple functions and eliminate several additional process steps that are
required in the fabrication of high-efficiency Si solar cells [42].
PECVD is a method of forming a thin solid film on a substrate by reaction of
vapor phase chemicals which contain the required constituents. The reactant gases are
activated by plasma energy and react on a temperature-controlled surface to form the thin
film. The reactive species, energy, rate of chemical supply and substrate temperature
largely determine the film properties.
The first publication specifically aimed at plasma-enhanced deposition for
semiconductor processing appeared in 1963 [44]. Two years later, PECVD technique was
invented [45]. This technique was soon utilized in IC technology and, in the mid-1970s,
in photovoltaic (PV) technology, when the first PECVD amorphous silicon (a-Si) thin
film solar cell was fabricated in RCA Laboratories by Carlson and Wronski in 1976 [46].
In 1981, for the first time, plasma SiN was applied to single-crystalline silicon metalinsulator-semiconductor
inversion-layer (MIS-IL) solar cell cells as a promising
dielectric [47, 48]. The first commercial cast me-Si solar cell process with SiN AR
coating was developed using available commercial equipment [49].
Since then, plasma SiN has been used by several large Si solar cell venders. To
name a few, Mobil Solar (now ASE America) incorporated plasma SiN into edge-defined