Deposition of device quality silicon nitride with ultra high deposition rate (ampersand gt 7 nm/s) using hot-wire CVD
article
The application of hot-wire (HW) CVD deposited silicon nitride (SiNx) as passivating anti-reflection coating on multicrystalline silicon (mc-Si) solar cells is investigated. The highest efficiency reached is 15.7% for SiNx layers with a N/Si ratio of 1.20 and a high mass density of 2.9 g/cm3. These cell efficiencies are comparable to the reference cells with optimized plasma enhanced (PE) CVD SiNx even though a very high deposition rate of 3 nm/s is used. Layer characterization showed that the N/Si ratio in the layers determines the structure of the deposited films. And since the volume concentration of Si-atoms in the deposited films is found to be independent of the N/Si ratio the structure of the films is determined by the quantity of incorporated nitrogen. It is found that the process pressure greatly enhances the efficiency of the ammonia decomposition, presumably caused by the higher partial pressure of atomic hydrogen. With this knowledge we increased the deposition rate to a very high value of 7 nm/s for device quality SiNx films, much faster than commercial deposition techniques offer [1].
TNO Identifier
845681
Publisher
ECN
Collation
15 p.
Place of publication
Petten
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