EFFECT OF HYDROGEN ON HOT-ELECTRON NOISE IN SHORT SAMPLES OF GAAS

We present experimental results on hot electron noise in untreated and hydrogenated samples of silicon-doped GaAs. Short n+-n-n+ structures are used to resolve noise sources arising from different mechanisms wh ich dominate electron scattering. Passivation of centres of impurity s cattering by hydrogen and the resultant effect on noise temperature an d spectral density of current fluctuations are clearly observed at int ermediate hydrogen doses (10(17) cm-2) low-field mobility of electrons increases, electron heating by electric field is favoured, noise sour ces due to GAMMA-L and GAMMA-X intervalley transfer and resonant scatt ering of hot electrons are better resolved, especially at low temperat ures. The effects at a hydrogen dose of 10(18) cm-2 suggest that the i mpurity passivation is accompanied by formation of new scattering cent res.