The redistribution of Mn in Si+ and Se+ implanted Cr-doped semi-insulating GaAs substrates is studied by secondary-ion mass spectrometry as a function of implant dose, energy, and annealing temperature subsequent to annealing capless and with a SiO2 cap in a As 4-H2 atmosphere. Mn accumulates within a depth of 0.5 μm from the GaAs surface with a peak at ∼500 Å from the surface for capless anneals. The Mn peak position is constant as the implant energy is varied. The role of the encapsulant in gettering Mn is described. The observed accumulation of Mn near the surface region of GaAs can cause p-type conversion of this region as reported by Klein. A higher solid solubility (≊ 3×1018 atoms/cm3) and a higher diffusion rate of Mn than of Cr in GaAs at 900°C are indicated by the dose study. A preliminary model for the Mn diffusion mechanism under the above conditions is proposed.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)