Impact of Copper-Doped Titanium Dioxide Interfacial Layers on the Interface-State and Electrical Properties of Si-based MOS Devices

摘要

The current study presents the interface-state and electrical properties of silicon (Si)-based metal-oxide-semiconductor (MOS) devices using copper-doped titanium dioxide (Cu:TiO2) nanoparticles for possible applications as an interfacial layer in scaled high-k/metal gate MOSFET technology. The structural properties of the Cu:TiO2 nanoparticles have been obtained by means of X-ray diffraction (XRD), UV-Vis-NIR spectrometry, atomic force microscopy, and scanning electron microscopy measurements; they were compared with pure TiO2 thin film. With the incorporation of Cu, rutile-dominated anatase/rutile multiphase crystalline was revealed by XRD analysis. To understand the nature of this structure, the electronic parameters controlling the device performance were calculated using current-voltage (I-V), capacitance-voltage (C-V), and conductance-voltage (G-V) measurements. The ideality factor (n) was 1.21 for the Al/Cu:TiO2/p-Si MOS device, while the barrier height I center dot (b) was 0.75 eV with semi-log I-V characteristics. This is in good agreement with 0.78 eV measured by the Norde model. Possible reasons for the deviation of the ideality factor from unity have been addressed. From the C-V measurements, the values of diffusion potential, barrier height, and carrier concentration were extracted as 0.67, 0.98 eV, and 8.73 x 10(13) cm(-3), respectively. Our results encourage further work to develop process steps that would allow the Cu-doped TiO2 film/Si interface to play a major role in microelectronic applications.