ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
Careful measurements have been made of the temperature dependence of the barrier height (φb) and the Richardson constant (A**c) for several metal/GaAs (111)B Schottky diodes using current-voltage and capacitance-voltage techniques. The metals used, aluminium, copper, and gold, were evaporated at a base pressure of 10−10 Torr, to ensure no native oxide at the interface. The values obtained for the temperature dependence of the barrier height were −(4.3±0.1)×10−4 eV K−1 for all diodes except for the Cu/GaAs (111)B diode where it was −(4.7±0.1)×10−4 eV K−1. The calculated Richardson constants were 0.51×104, 0.88×104, and 1.37×104 A m−2 K−2 for the Al, Au, and Cu GaAs (111)B diodes respectively, and 0.50×104 A m−2 K−2 for the Al/GaAs (100) comparison diode. The exactness of results between the Al/GaAs (111)B and the Al/GaAs (100) Schottky diodes is believed to indicate the formation of a thin interfacial layer of AlAs, probably formed during the metal evaporation. It was found that the semiconductor orientation had a subtle effect upon the Richardson constant compared to similar Schottky diodes fabricated on (100) GaAs. The variation in A**c indicates that the band structure of the metal plays a part in the formation of a Schottky barrier, and the similarity in the value of α indicates that the barriers are pinned relative to the same position. In comparison to the GaAs band gap variation with temperature, this appears to be pinned relative to the valence band of the semiconductor.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.355169
