PREPARATION AND CHARACTERISATION OF Ti/BaTiO3/InP MIS STRUCTURES

Abstract

Indium Phosphide (InP) is one of the most promising materials for high-speed electronic and optoelectronic devices. In the present investigation n-type InP substrates of <111> orientation grown by LEC technique in our laboratory were used to study the surface state densities. The wafer was polished with HBr:K 2 Cr 2 O 7: H 2 O (BCA) polishing solution and decreased with organic solvents. Au:Ge was used has a back ohmic contact and the wafer was annealed at 623K for 5 min. under nitrogen ambient. Barium Titanante ( BaTiO 3), a dielectric material was used as an insulator to fabricate InP -MIS structures. BaTiO 3 thin film has been deposited on InP substrates by sol-gel technique through organic precursor route. Titanium metal contact was made on the BaTiO 3 to obtain MIS structure. Compositional analysis of the BaTiO 3 thin film on InP substrates has been carried out using XPS and EDX. By the Capacitance Voltage measurements a minimum surface state density ( N ss) value as low as 4.5 × 1010 cm -2 eV -1 has been obtained for Ti/BaTiO 3/ InP MIS structures which is comparatively less than that of other deposited insulators.