Modelization and characterization of Au/InSb/InP Schottky systems as a function of temperature

This work attempts to characterize the Au/InP Schottky diode at different temperatures (in the range 300-425 K). The InP surface is restructured with an InSb thin film with several monolayers. I(V) analysis versus different temperatures gives the saturation current variation I-s(2 x 10(-5)-7 x 10(-5) A), the mean ideality factor (1.7-1.24), the barrier height (0.47-0.45 V), and finally the serial resistance R-s variations (85-19 Omega). The doping concentration N-d and the diffusion voltage V are calculated using the C(V) characteristics. The concentration N-d is 3 x 10(15) cm(-3) at room temperature and increases with thermal activation to 7 x 10(15) cm(-3) at 425 K. Nevertheless, the diffusion voltage V-d is reversibly proportional to the doping concentration N-d and decreases from 33.7 x 10(-2) to 29 x 10(-2) V. The mean interfacial state density N-ss decreases with increasing temperature, from 4.33 x 10(12) to 10(12) cm(-2).eV(-1). This improvement is the result of molecular restructuring and reordering at the Au/InP interface. For temperatures less than 375 K, the C(V) characteristic is controlled by an important interfacial state density and/or the presence of deep donor levels in the semiconductor bulk. At temperatures greater than 375 K, the C-2(V) curve is linear and the deep donor levels disappear; The traps effect is also reduced. (C) 1998 Elsevier Science S.A. All rights reserved.