Correlated annealing and formation of vacancy-hydrogen related complexes in silicon

I L Kolevatov,E V Monakhov,B G Svensson

doi:10.1088/1361-648x/ab0bf2

Abstract

We report on a deep level transient spectroscopy study of annealing kinetics of a deep, vacancy-hydrogen related level, labeled E5*, at 0.42 eV below the conduction band in hydrogen-implanted n-type silicon. The E5* annealing correlates with the formation of another commonly observed vacancy-hydrogen related level, labeled E5, at 0.45 eV below the conduction band. The annealing of E5* and the formation of E5 exhibit first-order kinetics with an activation energy of 1.61 ± 0.07 eV and a pre-factor of ~1013–1014 s−1. The pre-factor indicates a dissociation or structural transformation mechanism. The analysis of electron capture cross-sections for E5* and E5 reveals considerable transition entropies for both states and a temperature dependent capture cross-section for E5*. Two possible identifications of E5* and E5 are put forward. Firstly, E5* can be attributed to V2H2(−/0) or V2H3(−/0), which dissociate with the emission of VH (E5). Secondly, E5* and E5 can be assigned to two different configurations of V3H.

Highlights

Hydrogen (H) is probably the most common and, at the same time, controversial impurity in silicon
We report on a deep level transient spectroscopy study of annealing kinetics of a deep, vacancy-hydrogen related level, labeled E5*, at 0.42 eV below the conduction band in hydrogen-implanted n-type silicon
E5* can be attributed to V2H2(−/0) or V2H3(−/0), which dissociate with the emission of VH (E5)

Summary

Introduction

Hydrogen (H) is probably the most common and, at the same time, controversial impurity in silicon. It can be found in a form of atomic interstitial species (Hi) [1], dimers (H∗2) [2] and molecules (H2) [3]. Hydrogen is a crucial impurity in silicon technology due to the ability to passivate dangling bonds. Recently there have been observed indications that hydrogen may have an effect on the so-called light-induced degradation of solar cells [5,6,7]. We have reported on a hydrogen-related level, labeled as E5* [8]. The level forms during heat treatments in the temperature range 75 °C–95 °C and has a position at Ec − 0.42 eV (Ec being the conduction band minimum) and an apparent capture cross-section (CCS) of 4 × 10−17 cm

Results

Discussion

Conclusion