Ti/p-Si Schottky barrier diodes with interfacial layer prepared by thermal oxidation

Abstract

We have identically prepared as many as 70 MIS (metal/insulating/semiconductor) Ti/p-Si Schottky barrier diodes (SBDs) with interfacial oxide layer and 70 MS (metal/semiconductor) Ti/p-Si SBDs without interfacial oxide layer for a statistical study. The oxide layer on a chemically cleaned Si surface was obtained by thermal oxidation before metal evaporation. The influence of thermal oxidation on Schottky barrier formation at the Si (1 0 0) surface upon subsequent metal deposition was investigated. The values of 1.087 and 0.584 eV for the mean ideality factor and effective barrier height of the reference (without interfacial layer) MS Ti/p-Si SBDs were obtained from current–voltage ( I– V) characteristics, respectively. The values of 1.240 and 0.761 eV for the mean ideality factor and effective barrier height of MIS Ti/p-Si SBDs with the thin oxide layer, respectively, were obtained from I– V characteristics. The transport properties of the metal–semiconductor contacts were observed to be drastically affected by the presence of the interfacial oxide layer. Thus, the barrier height was increased by 177 meV for Ti/p-Si by means of the thermal oxide. Furthermore, we have calculated a mean tunneling barrier height of χ = 0.31 eV for the MIS Ti/p-Si SBDs with interfacial oxide layer.