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Indium phosphide (InP) is one of the most promising materials for applications in high speed and optoelectronic devices. Indium phosphide presents a high mobility and large band gap. However, the elaboration of InP components shows problems in the technology [L. Bideux, B. Gruzza, A. Porte, Surf. Interf. Anal. 20 (1993) 803–807; G. Hollinger, J. Appl. Phys. 67 (1990) 4173], because phosphorus is very volatile. Before the deposition of insulator and metal, InP surface is treated and well passive to get optimal conditions for the elaboration of electronic structure. We have shown that InSb buffer can reduce the phosphorus atoms migration and the defects at the interface [L. Bideux, C. Robert, B. Gruzza, V. Matolin, Z. Benamara, Surf. Sci. 352–354 (1996) 407–410]. After the elaboration of Au/InP, Au/InSb:InP, Al2O3/InP and Al2O3/InSb:InP structures, we have studied and characterized electrically these structures. The results obtained show clearly the reduction of the defects in the structures protected by InSb buffer layer and no treated surface compared with the InP ones.

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 Is (2×10−5–7×10−5 A), the mean ideality factor (1.7–1.24), the barrier height (0.47–0.45 V), and finally the serial resistance Rs variations (85–19 Ω). The doping concentration Nd and the diffusion voltage Vd are calculated using the C(V) characteristics. The concentration Nd is 3×1015 cm−3 at room temperature and increases with thermal activation to 7×1015 cm−3 at 425 K. Nevertheless, the diffusion voltage Vd is reversibly proportional to the doping concentration Nd and decreases from 33.7×10−2 to 29×10−2 V. The mean interfacial state density Nss decreases with increasing temperature, from 4.33×1012 to 1012 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.