The effects of rapid thermal annealing upon the properties of C-doped epilayers were studied by means of Van der Pauw-Hall measurements. After rapid thermal annealing, the highest hole concentration (3.3 x 1020/cm3) was found in Ga0.91In0.09As epilayers. The rapid thermal annealing caused inactivated C atoms to become active by breaking C-H or C-Hx bonds. This led to an increase in the hole concentration. Below an InAs mole fraction of 0.35, the maximum activation efficiency of C atoms was obtained at a rapid thermal annealing temperature of 650C. The activation efficiency decreased with increasing InAs mole fraction. Conversion from p-type to n-type took place after rapid thermal annealing of material with an InAs mole fraction of 0.44, but it occurred at a mole fraction of 0.48 in as-grown samples. The type-conversion shift to lower value mole fractions, after rapid thermal annealing, was attributed to the out-diffusion of In atoms from the InGaAs epilayer. Activated C atoms were expected to be more likely to enter In sites than As sites, due to the out-diffusion of In.

C.S.Son, S.I.Kim, T.G.Kim, Y.Kim, M.S.Kim, S.K.Min: Solid State Communications, 1996, 98[5], 475-8