Defects in high purity GaAs grown by low pressure metalorganic chemical vapour deposition

Abstract

Unintentionally doped epitaxial GaAs layers grown by low pressure metalorganic chemical vapour deposition have been studied by deep level transient spectroscopy. The study reveals the presence of four electron traps, the dominant one (1013 cm-3) being associated with the so-called EL2 defect. The other ones exhibit ionization energies of 0.32, 0.47 and 0.65 eV. The 0.32 eV trap, located in the surface region, is the EL6 defect commonly encountered, like the EL2 one, in epitaxial as well as bulk materials.