Profiles which reflected the passivation of electrically active and recombination-active centres by atomic H in single crystals were investigated by using secondary ion mass spectrometry and microcathodoluminescence methods. The former data indicated that the profiles were the same for all of the samples, and consisted of an 0.0005mm surface region with a H content of 1020/cm3 and a low diffusion rate. This was followed by a diffusion tail with a much higher diffusion rate. In this tail region, the activation energy for H diffusion was 0.83eV at temperatures of between 200 and 500C (table 19), and the diffusivity was 6.7 x 10-9cm2/s at 400C. It was proposed that the results confirmed the suggested migration of neutral interstitial H. The introduction of atomic H completely suppressed a microcathodoluminescence inhomogeneity which was associated with dislocations in the semi-insulating material.

E.M.Omelyanovskii, A.V.Pakhomov, A.J.Polyakov, A.V.Govorkov, O.M.Borodina, A.S.Bruk: Fizika i Tekhnika Poluprovodnikov, 1988, 22[7], 1203-7. (Soviet Physics - Semiconductors, 1988, 22[7], 763-5)

Table 19

Diffusivity of H in GaAs