A study of Be diffusion in InGaAsP layers grown by gas-source molecular beam epitaxy

The redistribution of the p-type dopant Be during rapid thermal annealing a fter their growth of InGaAsP layers grown by gas-source molecular beam epit axy has been studied using secondary ion mass spectrometry. The experimenta l structure consisted of a 0.2 mu m Be-doped (3 x 10(19) cm(-3)) In0.73Ga0. 27As0.58P0.42 layer sandwiched between 0.5 mu m undoped In0.73Ga0.27As0.58P 0.42 layers. A kick-out model of the substitutional-interstitial diffusion mechanism, which involves neutral interstitial Be species and positively ch arged group III self-interstitials, is proposed in order to explain the obs erved depth profiles. As a result of this work, we suggest a complete set o f parameters which describes the diffusion of Be in quaternary epitaxial la yers in the temperature range 700-900 degrees C.