LOW-TEMPERATURE MBE GROWN ALINAS - INVESTIGATION OF CURRENT-VOLTAGE AND LOW-FREQUENCY NOISE BEHAVIOR OF SCHOTTKY DIODES

The electrical characteristics of Schottky diodes fabricated on AlInAs layers grown on InP (100) substrates by molecular beam epitaxy in the temperature range 300 to 550 degrees C were investigated by means of current-voltage and low frequency noise (LFN) measurements. Owing to t he presence of deep level impurities in the layers, the decrease of th e effective Schottky barrier height with measurement temperature below 160 K can be described by a two-step defect-assisted tunnelling proce ss. The observed low frequency 1/f(alpha) (1 < alpha < 2) noise is att ributed to the modulation of the Schottky barrier height arising from fluctuations in the occupancy of deep traps distributed within the AlI nAs layers. From temperature dependent LFN measurements, we have ident ified two deep electron traps labelled L2 and L3, located respectively at 0.4 +/- 0.1 eV and 0.66 +/- 0.06 eV below the conduction band mini mum. (C) 1997 Elsevier Science Ltd.