Title :
Field and Temperature Dependent Life-Time Limiting Effects of Metal-GaAs Interfaces of Device Structures Studied by XPS and Electrical Measurements
Author :
Wurfl, J. ; Hartnagel, H.L.
Author_Institution :
Institut fÿr Hochfrequenztechnik, Technische Hochschule Darmstadt, MerckstraÃ\x9fe 25, 6100 Darmstadt, FRG
Abstract :
Typical Schottky contacts for GaAs devices such as Al and TiPtAu metallizations have been accelerated-stress tested under bias at room temperature and at temperatures up to 250° C. The influence of these stress tests on the interface properties were studied by XPS sputter profiling and correlated with electrical measurements. Concerning Al-contacts it has been found that bias-stressing results in a structural change of the Al layer and that the oxygen concentration at the Al-GaAs transition depends both on the polarity of bias stressing and on the GaAs surface treatment before Al-metallization. These effects are quite pronounced even at room temperature. TiPtAu contacts are stable at room temperature over the period of investigation (200 h) but at elevanted temperatures (200° C) a GaAs diffusion into Ti and a subsequent Ti diffusion into Ga vacancies could be observed. This results in a catastrophic bias dependent degradation of the I/V characteristics.
Keywords :
Degradation; Electric variables measurement; Gallium arsenide; Life estimation; Metallization; Schottky barriers; Stress measurement; Surface treatment; Temperature dependence; Testing;
Conference_Titel :
Reliability Physics Symposium, 1986. 24th Annual
Conference_Location :
Anaheim, CA, USA
DOI :
10.1109/IRPS.1986.362124