From micro- to nanotransport properties in Pr2O3-based thin layers

In this paper, the conduction mechanisms in Si/SiO2/PrxSiyOz/Pr2O3/Au metal-insulator-semiconductor capacitors have been investigated. The dielectric stack has been produced by metal-organic chemical-vapor deposition. Nanoscopic and microscopic capacitance properties have been correlated. The capacitance-voltage (C-V) characteristics of 25-mu m-radius metal-oxide-semiconductor capacitors have been evaluated and compared to the measurements performed by scanning capacitance microscopy (SCM). The study of the SCM images allows us to confirm the value of interface state density (D(it)approximate to 10(12) cm(-2) eV(-1)) obtained by C-V investigation excluding any defect or grain-boundary contribution in the capacitance phenomena. The conduction mechanisms have been investigated by current-density-voltage (J-V) measurements performed at different temperatures (from 100 to 200 degrees C). At low electric fields, a slight dependence of J-V characteristics in function of both temperature and electric field has been observed, while a relatively strong dependence at high fields has been found. Hill's diagram indicated that at high electric fields the conduction follows the Poole-Frenkel mechanism. Finally, Hill's diagram points out that the traps contributing to the conduction phenomena are approximately at the midgap value.