Effects of boron incorporation on the structural, optical and electrical properties of sol–gel-derived ZrO2 gate dielectrics

The effect of boron (B) doping on the microstructure, band gap energy and electrical properties of ZrO2 gate dielectrics deposited by sol–gel method at low temperature were systemically investigated. By means of characterization of spectroscopy ellipsometry and ultraviolet–visible spectroscopy, the thicknesses and optical constants of ZrO2 gate dielectrics have been determined precisely. The B incorporation dependent electrical properties of ZrO2 films were determined by capacitance–voltage (C–V) and leakage current density–voltage (J–V) measurements. The dominant conduction mechanisms of Al/B:ZrO2/n-Si MOS structures have been discussed systematically in detail. As a result, the optimized B incorporation content has been obtained to achieve ZrO2 gate dielectrics with high quality.