Thermal stability of TaSix/n-GaAs metallizations

Abstract TaSi 0.47 diodes on n -GaAs have been shown by I – V measurements to have better thermal stability than TaSi 1.25 and TaSi 2.40 metallizations. Further characterizations by electrical ( C – V ) and microstructural (secondary ion mass spectrometry, Rutherford backscattering spectroscopy, X-ray diffraction and scanning electron microscopy) analyses have been performed on TaSi 0.47 / n -GaAs contacts. On annealing up to 600°C only a moderate increase of the barrier height was detected. At 700°C, the beginning of interfacial reactions was detected by secondary ion mass spectrometry, accompanied by a barrier increase up to 0.85 V. At higher annealing temperatures large inhomogeneous reactions have been observed as well as carrier compensation phenomena in the GaAs interfacial region, but without any significant degradation of the diode rectifying properties.