Electrical properties of Te-doped MOCVD grown GaSb Schottky diodes

Dimethyltelluride has been used as a dopant source for GaSb epilayers grown by atmospheric pressure MOCVD (Metalorganic Chemical Vapour Deposition). Schottky diodes were fabricated using Al barriers and Au-Ge-Ni as Ohmic contact. Doping densities of about 4./spl times/x10/sup 18/ cm/sup -3/ and barrier heights of 0.63 eV are found from C-V measurements, compared to 0.59 eV determined from room temperature I-V measurements. Room temperature ideality factors are around 1.3, while its variation with temperature demonstrates the role of electron tunnelling through the depletion barrier. The carrier concentration probed by C-V is confirmed by van der Pauw Hall measurements. The effect of thermal annealing on the diodes is also reported.