Study of electrical and chemical profiles of Si implanted in semi-insulating GaAs substrate annealed under SiO2 and capless

Abstract

We have studied, compared, and correlated the chemical redistribution of Cr and Si, electrical profiles, mobilities, carrier concentrations, and channel conduction currents in Si‐implanted semi‐insulating GaAs substrates annealed with and without a SiO₂ cap under an As₄ and H₂ ambient for 20 min at 830 and at 860 °C. Differences observed between capless and SiO₂‐encapsulated annealing methods include the position and activation of net donor concentration peaks, the gradient of the leading edge of the profiles, and mobilities. An explanation of these differences is provided using a Cr redistribution model and a charge neutrality equation where this complex electrical behavior cannot be explained solely by the implanted impurity atoms and thermal diffusion effects.