Hydrogen–boron complex formation and dissociation in 4H–silicon carbide

Abstract

The diffusion of deuterium ( 2H) in p-type 4H–silicon carbide (SiC) has been studied in detail by secondary ion mass spectrometry. An effective capture radius for the formation of 2H–B complexes at 460 °C is determined to R HB =(21±4) A ̊ . This value is in good agreement with that expected for a coulomb force-assisted trapping mechanism. At higher temperatures, the 2H diffusion follows Fick’s law with a constant effective diffusivity from which the complex dissociation frequencies ν HB are determined. The frequencies exhibit an Arrhenius temperature dependence over the three orders of magnitude covered by the extracted ν HB. The complex dissociation energy is determined to E d HB =(2.51±0.04) eV which is 0.9 eV larger than the corresponding value for the 2H–Al complex, suggesting that the atomic configurations for the two complexes are significantly different. The extracted dissociation attempt frequency, ν 0 HB =(1.2±0.7)×10 13 s −1 is very close to the characteristic oscillation frequency of the SiC lattice, ν lattice SiC =1.6×10 13 s −1 . In addition, 2H diffusion in an epitaxial Al multilayer structure demonstrates the influence of internal electric fields on the 2H diffusion in p-type SiC.