Electrical Characterization of TbScO₃/TiN Gate Stacks of MOS Capacitors and MOSFETs on Strained and Unstrained SOI

Abstract

We investigated the electrical and structural properties of TbScO 3 as an alternative gate dielectric. Rutherford backscattering spectrometry revealed a stoichiometric film while X-ray photo-electron spectroscopy indicated silicate formation at the interface. Capacitance-Voltage measurements resulted in well behaving C-V curves with no hysteresis and a low density of interface trap states in the range of 4x10 11 (eVcm 2 ) -1 . Fully depleted (FD) SOI and sSOI MOSFETs fabricated with a full replacement gate process show a steep subthreshold slope down to 81 mV/dec and high I on /I off ratios up to 10 8 . Low field electron mobilities of 181 cm 2 /Vsec for SOI and 350 cm 2 /Vsec for sSOI, were extracted, which are comparable to MOSFETs with Hf based oxides. Gate induced drain leakage (GIDL) investigations indicate a trap assisted band to band tunneling.

Electrical and Structural Properties of Ternary Rare-Earth Oxides on Si and Higher Mobility Substrates and their Integration as High-k Gate Dielectrics in MOSFET Devices

“…The curve exhibits no humps or irregularities and is almost free of hysteresis. The D it values for LaLuO 3 and also for scandate films on Si are typically in the range of 1 to 5x10 11 eV -1 cm -2 [45][46][47]53]. …”

“…Fully depleted n-and p-MOSFETS were processed on SOI, sSOI (Si on insulator and sSi on insulator, respectively), and SiGe substrates. More details can be found elsewhere [30,[44][45][46][47].…”