The diffusion of ion implanted hydrogen in amorphous Si₃N₄:H films

Abstract

The tracer diffusion of hydrogen is studied in amorphous Si 3 N 4 :H films which were produced by rf magnetron reactive sputtering. The diffusion experiments were carried out in the temperature range between 700 and 1000 • C with ion implanted deuterium isotopes. Secondary ion mass spectrometry was used for depth profile analysis. While a considerable part of the tracer is immobilized due to the interaction with the implantation damage, the other part migrates freely into the film, wherefrom diffusivities are extracted. These diffusivities coincide with those obtained from a control experiment with a gas exchange technique, demonstrating that the implantation damage has no significant influence on the determination of the correct diffusivities themselves. 2 H transport can be described by the concept of trap limited diffusion, where the tracer atoms are temporarily trapped by intrinsic film defects, presumably nitrogen dangling bonds. For the present case of a considerably high dissociation rate of trapped hydrogen, effective diffusivities are derived which obey an Arrhenius behaviour with a large activation energy of E = 3.4 eV and a pre-exponential factor of D 0 = 5 × 10 −4 m 2 s −1 . The effect on diffusion of pre-annealing the films prior to diffusion in nitrogen and possible structural rearrangements involved, as well as of charging the films with hydrogen up to 2.6 at.%, is analysed.

Trap-limited diffusion of hydrogen in precursor derived amorphous Si–B–C–N-ceramics

“…The activation enthalpy for hydrogen diffusion in amorphous SiC with a lower hydrogen content of 0.4 at.% is found to be (3.2 ± 0.2) eV [27]. A similar effect can be observed for amorphous Si 3 N 4 [20]. For samples with a hydrogen content of 0.2 at.% the activation enthalpy for the diffusion of hydrogen is (3.4 ± 0.2) eV but for samples with a hydrogen content of 2.6 at.% the activation enthalpy for the diffusion of hydrogen is (2.6 ± 0.2) eV.…”

“…[19] and for amorphous Si 3 N 4 films from Ref. [20]. The precursor derived ceramic referred to as T2/1C was produced from a precursor different from the precursor of the MW33C ceramic [21] and was thermolyzed at 1400°C.…”

Effects of high-temperature treatment on the hydrogen distribution in silicon oxynitride/silicon nitride stacks for crystalline silicon surface passivation

“…Thus a high amount of free atomic hydrogen is located at the layer interfaces. According to the literature [22][23][24] atomic hydrogen slowly diffuses through SiN, whereas molecular hydrogen (H 2 ) diffuses much faster. So the SiN layer acts as a diffusion barrier to atomic hydrogen.…”

Diffusion in Si3N4

“…Schmidt et al (2004a). With kind permission of Dr. Schmidt (sample SN1000HG) measured with SIMS after annealing at elevated temperatures and annealing times using a gas-exchange technique.…”

“…(15.3) with D and k s as fitting parameters. Schmidt et al (2004a). With kind permission of Dr. Schmidt penetration of the 2 H tracer into the film without changing the overall H-content of the sample.…”