Molecular beam epitaxy grown template for subsequent atomic layer deposition of high κ dielectrics

Abstract

Molecular beam epitaxy (MBE) grown high κ dielectrics of Al2O3 and HfO2 are employed as templates to suppress effectively the oxide/Si interfacial layer formation during the subsequent atomic layer deposition (ALD) growth. The absence of the interfacial layer was confirmed using x-ray photoelectron spectroscopy and high resolution transmission electron microscopy. Two composite films consisting of ALDAl2O3(1.9nm)∕MBEAl2O3(1.4nm) and ALDAl2O3(3.0nm)∕MBEHfO2(2.0nm) showed overall κ values of 9.1 and 11.5, equivalent oxide thicknesses of 1.41 and 1.7nm, Dit of 2.2×1011 and 2×1011cm−2eV−1, and leakage current densities of 2.4×10−2A∕cm2 at Vfb−1V and 1.1×10−4A∕cm2 at Vfb+1V, respectively. The attainment of high dielectric constant suggests that there is no low κ capacitor in series near the oxide/Si interface.

Molecular beam epitaxy-grown Al2O3/HfO2 high-κ dielectrics for germanium

“…Two inch Sb-doped n-type Ge(1 0 0) wafers with a resistivity about 3.9-4.4 O cm and Ga-doped p-type Ge(1 0 0) wafers with a resistivity about 0.01-0.03 O cm were dipped in a 2% dilute hydrofluoric solution and rinsed in de-ionized water, and were immediately loaded into the multi-chamber UHV/MBE system with in-situ characterization [5]. An atomically ordered, oxide-free Ge surface was then obtained by thermal desorption of native oxides with the substrates being heated up to 450 1C, as evidenced by sharp, streaky 2 Â 2 reconstructed reflection high energy electron diffraction (RHEED) patterns ( Fig.…”

“…In this work, deposition of Al 2 O 3 /HfO 2 bi-layers on Ge and the Al 2 O 3 /HfO 2 /Ge interfacial chemical characterization were performed in a multi-chamber ultra-high vacuum (UHV) system consisting of several MBE chambers and angle-resolved X-ray photoelectron spectroscopy (AR-XPS), all being connected via UHV of 10 À10 Torr [5]. Al 2 O 3 /HfO 2 was directly deposited by electron beam evaporation on UHV-annealed Ge surface without any interfacial barrier layers.…”

Research advances on III–V MOSFET electronics beyond Si CMOS

“…A composite film consisting of ALD-Al 2 O 3 (3.0 nm)/MBE-HfO 2 (2.0 nm) showed an overall k value of 11.5, a capacitance equivalent thickness (CET) of 1.7 nm, a D it of 2 Â 10 11 cm À2 eV À1 , and a leakage current density of 1.1 Â10 À4 A/cm 2 at V fb +1 V as in Fig. 1(d) [11]. Here a CET is defined as k SiO 2 Ã(thickness of high-k dielectrics)/(k high k ).…”

“…Such nano-thick high-k dielectric films were employed as a template to suppress the formation of unwanted oxide/Si interfacial layer during subsequent ALD, as illustrated in Fig. 1(a-c) [11]. The attainment of high k and very small frequency dispersion in capacitancevoltage (C-V) curves suggests the absence of low k capacitors in series near the oxide/Si interface.…”

GaN metal-oxide-semiconductor diodes with molecular beam epitaxy-Al2O3 as a template followed by atomic layer deposition growth

“…The study of HCl-cleaned GaN surface and the deposition of Al 2 O 3 film has been carried out in a multi-chamber MBE system, including UHV oxide deposition chambers, XPS analytical chamber, and in situ transfer modules, which connect all the functional chambers [15]. Metalorganic chemical vapor deposition (MOCVD) grown n-type GaN (c-plane (0 0 0 1)) on sapphire substrates were cleaned with hydrochloric acid solution (HCl: D.I.…”