Study of the Characteristics of HfO2/Hf Films Prepared by Atomic Layer Deposition on Silicon

다국어 초록 (Multilingual Abstract)

Hafnium-oxide (HfO$_2$) thin films were deposited on p-type (100)
silicon wafers by using atomic layer deposition (ALD) with tetrakis
(ethylmthylamino)-hafnium [TEMAH] and ozone. Prior to the deposition
of the HfO$_2$ thin films, a thin Hf (10 \AA) metal layer was
deposited. The deposition temperature of the HfO$_2$/Hf thin film
was 350 $^\circ$C and, its total thickness was 150 \AA. The
deposited samples were annealed in a furnace under nitrogen ambient.
Round-type MOS capacitors were fabricated with Pt electrodes
prepared by using an e-beam evaporator. We observed the formation of
Hf-O-Si bonds, instead of Si-O bonds, at the interface. The HfSiO
layer was grown between the HfO$_2$ and Si; therefore, the Hf metal
layer sandwiched in the HfO$_2$/Si structure was effectively
suppressed to grow interfacial SiO$_x$. The MOS capacitance of the
HfO$_2$/Hf/Si structure was larger than that of the HfO$_2$/Si
structure. The dielectric constant of the HfO$_2$/Hf layer was
$\sim$18.96, and the interface state density at the silicon
interface was 2.2 $\times$ 10$^{-12}$ cm$^{-2}$eV$^{-1}$.