Beryllium diffusion in InGaAs/InGaAsP structures grown by gas source molecular beam epitaxy

A systematic study of Be post-growth diffusion from buried Be-doped InGaAs layers in undoped InGaAsP layers grown by gas source molecular beam epitaxy was carried out. The experimental structures consisted of a 2000 Angstrom Be-doped (3 x 10(19) cm(-3)) In0.53Ga0.47As layer sandwiched between 5000 A ngstrom undoped In0.73Ga0.27As0.58P0.42 layers. The samples were subjected to rapid thermal annealing in the temperature range from 700 to 900 degrees C with time durations of 10-240 s. Secondary ion mass spectrometry was emp loyed for a quantitative determination of the Be depth profiles. To explain the obtained experimental results, the kick-out model of substitutional-in terstitial diffusion mechanism, involving neutral Be interstitial species a nd positively charged Ga and In self-interstitial species, has been conside red. The Be and self-interstitial diffusivities, the rate coefficient of se lf-interstitial generation or annihilation, the self-interstitial equilibri um concentration, and the intrinsic carrier concentration were obtained for ternary and quaternary layers as functions of temperature, (C) 2000 Elsevi er Science S.A. All rights reserved.