We fabricated TaN gate electrodes on SiO2 film by wet etching using NH4OH/H2O2 solution and investigated the electrical and structural properties of the TaN/SiO2 interfacial layer. Hf metal was used as a hard mask for the wet etching of the TaN film. It was found that the gate patterning of the TaN film was successfully achieved by wet chemical etching, which should be applicable for dual-metal-gate fabrication. The effective fixed charge density (Qeff) into the SiO2 film and the effective work function (Φm,eff) of TaN remained constant after N2 annealing at temperatures of up to 750°C but increased after annealing at 900°C. The analysis by X-ray photoelectron spectroscopy (XPS) indicated that Ta oxide was formed near the TaN/SiO2 interface after the annealing at 900°C. The increases in Qeff and Φm,eff are discussed on the basis of the XPS results.
All Science Journal Classification (ASJC) codes
- General Engineering
- General Physics and Astronomy