Hydrogen-plasma etching of hydrogenated amorphous silicon: a study by a combination of spectroscopic ellipsometry and trap-limited diffusion model

Experimental evidence for extended hydrogen diffusion in silicon thin films during light-soaking

“…During the first two hours of bluelight-soaking, electron-hole pairs generated at the vicinity of the glass substrate lead to the formation of mobile hydrogen which has to diffuse through the sample before leaving it and being detected by the mass spectrometer. Considering the film thickness (0.22 lm) and the time required by hydrogen to cross the sample, we deduce a hydrogen diffusion coefficient of 5 · 10 À14 cm 2 /s, in agreement with previous studies [8].…”

Surface passivation of c-Si for silicon heterojunction solar cells using high-pressure hydrogen diluted plasmas

“…We think that this is associated to the temperature dependence of the etching effect when high H 2 diluted plasmas are used during the growth. 40 The effective deposition rate is a competition between the growth due to radicals and ions sticking to the surface, and the hydrogen induced etching of the material. At higher temperatures the etching is quenched, resulting in higher effective deposition rate.…”

Remote plasma deposition of microcrystalline silicon thin-films: Film structure and the role of atomic hydrogen

“…Since atomic hydrogen, which is abundant in the plasma, is known to preferentially etch a-Si:H [23,24] and induces the formation of H-rich sub-surface layer [25], Discussion section 4.2 addresses a possible competition between film growth and H-induced etching of a-Si:H, and between film growth and H-induced surface/film modification ("chemical annealing"). we show in Fig.…”

“…The surface modification induced by atomic H, which has a substrate-temperature-dependent penetration depth [25], extends to the top 15-50 nm, as determined by spectroscopic ellipsometry (e.g. Fig.…”

“…In particular, atomic hydrogen can be considered responsible for the above-described material properties since it is known to preferentially etch a-Si:H [23,24]. Furthermore, previous studies on the interaction of atomic H with a-Si:H films have reported on the formation of an H-rich subsurface layer [25], caused by the insertion of atomic H into strained Si\Si bonds [26,27]. Therefore, we have exposed a-Si:H films to an atomic H flux and investigated the competition between film growth and H-induced etching of a-Si:H, and between film growth and H-induced surface/film modification ("chemical annealing").…”