F. J. J. Peeters

High-rate plasma-deposited SiO2 films for surface passivation of crystalline silicon

SiO2 films were deposited by means of the expanding thermal plasma technique at rates in the range of 0.4–1.4μm∕min using an argon∕oxygen∕octamethylcyclotetrasiloxane (OMCTS) gas mixture. The film composition was studied by means of various optical and nuclear profiling techniques. The films deposited with a low OMCTS to oxygen ratio showed no residual carbon and a low hydrogen content of ∼2% with a refractive index close to thermal oxide. For a higher OMCTS to oxygen ratio a carbon content of ∼4% was detected in the films and the refractive index increased to 1.67. The surface passivation of the SiO2 films was tested on high quality crystalline silicon. The films yielded an excellent level of surface passivation for plasma-deposited SiO2 films with an effective surface recombination velocity of 54cm∕s on 1.3Ωcm n-type float zone crystalline silicon substrates after a 15min forming gas anneal at 600°C.

Good Surface Passivation of C-SI by High Rate Plasma Deposited Silicon Oxide

Silicon dioxide films were deposited by the (industrially applied) expanding thermal plasma technique using a gas mixture of argon-oxygen-octamethylcyclotetrasiloxane (OMCTS) and at deposition rates in the range of 5-23 nm/s. The films composition was investigated by means of spectroscopic ellipsometry, Fourier transform infrared spectroscopy and Rutherford backscattering. The composition was close to that of thermal oxide, with only a small residual hydrogen content of 2 at.%. The surface passivation of the silicon dioxide films was tested on 1.3Omegacm n-type FZ crystalline silicon wafers. A good level of surface passivation of 54 cm/s was reached after a 15 minute forming gas anneal at 600 degC

Atomic hydrogen induced defect kinetics in amorphous silicon

Near-infrared evanescent-wave cavity ring-down spectroscopy (CRDS) has been applied to study the defect evolution in an amorphous silicon (a-Si:H) thin film subjected to a directed beam of atomic H with a flux of (0.4–2) × 1014 cm−2 s−1. To this end, a 42 ± 2 nm a-Si:H film was grown on the total internal reflection surface of a folded miniature optical resonator by hot-wire chemical vapor deposition. A fully reversible defect creation process is observed, with a nonlinear dependence on H flux, with a time resolution of 33 ms and a relative sensitivity of 10−7. Using polarizing optics, the CRDS signal was split into s- and p-polarized components, which, combined with E-field calculations, provides depth sensitivity. Extensive kinetic modeling of the observed process is used to determine rate constants for the hydrogen–material interactions and defect formation in a-Si:H, as well as revealing a high diffusion coefficient for atomic H on the order of 10−11 cm2 s−1. A novel reaction pathway is proposed, wher...

High-Quality Surface Passivation Obtained by High-Rate Deposited Silicon Nitride, Silicon Dioxide and Amorphous Silicon using the Versatile Expanding Thermal Plasma Technique

The expanding thermal plasma (ETP) is a novel plasma technique currently used by several solar cell manufacturers for the deposition of silicon nitride antireflection coatings on (multi-) crystalline silicon solar cells. In this paper we will show that the ETP technique is versatile and can be used for the deposition of silicon nitride, silicon dioxide and hydrogenated amorphous silicon with a good level of surface passivation. In this way the ETP technique can meet the future PV demands with respect to the decrease in wafer thickness and the use of n-type material that requires good electrical and optical quality thin films at both the front and the back side of the solar cell