A study of hydrogen diffusion in crystalline silicon by secondary-ion mass spectrometry

Abstract

The diffusion coefficient of hydrogen in crystalline silicon, obtained from recent profiling experiments such as nuclear resonance retention and secondary-ion mass spectroscopy, is 3–9 orders of magnitude smaller than the previously accepted value measured by Van Wieringen and Warmoltz in 1956. Here we point out several items often overlooked in the analysis of profiling measurements. A limited flux model is proposed to explain the observed results. Predictions by the model are supported by further experiments.

Simulation of hydrogen diffusion and boron passivation in crystalline silicon

“…As can be seen from Fig. 1, the calculated deuterium concentration profile is in good agreement with the experimental data of [10]. It follows from the fitting procedure that the increase of k HIA i or β HIA results in a more abrupt deuterium profile between the passivated and unpassivated regions.…”

“…Due to these features, the system of equations (3), (4), (5), and (6) is very convenient for numerical solution. It is also worth noting that the concentration of charge carriers χ can be calculated either from the assumption of local charge neutrality (10) or, more exactly, from the Poisson equation for electrostatic potential ϕ.…”

“…In addition, the hydrogen interstitials can be generated due to the rearrangement or dissolution of platelets which incorporate hydrogen atoms. Unfortunately, the energy of hydrogen ions was not mentioned in [10]. However, the thickness of the layer where generation occurs is negligible in comparison with the average migration length of hydrogen interstitials and character dimensions of the passivation region.…”

Formation, dissociation, and diffusion of various hydrogen dimers in silicon

“…However, there is a clear evidence against this notion. The in‐diffusion profiles produced at 200 °C for various exposure times show (Fig. ) a standard wide plateau where the hydrogen concentration is equal to N B = 10 18 cm −3 —a region where boron is completely converted into HB.…”

“…Hydrogen (deuterium) depth profiles in samples with N B = 10 18 cm −3 exposed to plasma at 200 °C for 5, 10, and 15 min (curves 1–3, respectively). The solid curves are fitted erfc‐like profiles, and the deduced diffusivity is 2.5 × 10 −14 cm 2 s −1 .…”