Si metal-oxide-semiconductor devices with high κ HfO2 fabricated using a novel MBE template approach followed by atomic layer deposition

Molecular beam epitaxy (MBE) was employed to grow nanothick high κ HfO2 films on Si (100) as templates to suppress the formation of the oxide/Si interfacial layer during the subsequent atomic layer deposited (ALD) HfO2 growth. A metal-oxide-semiconductor (MOS) diode with the ALD/MBE bilayer stack of an equivalent oxide thickness (EOT) of ∼1.1nm has demonstrated markedly low electrical leakage of 8.3×10−3A∕cm2 at Vfb−1V, a reduction by five order of magnitudes, comparing with those using SiO2 of the same EOT. The attainment of high dielectric constant and very small frequency dispersion in capacitance-voltage (C-V) curves suggests the absence of low κ capacitors in series near the oxide/Si interface. Furthermore, MOS field-effect transistors (MOSFETs) based on the ALD/MBE-HfO2 composites have been fabricated having excellent device performance, with a drain current (ID) of 240mA∕mm and transconductance (Gm) of 120mS∕mm. These are superior to those of the MOSFETs using either ALD (55mA∕mm, 60mS∕mm) or MBE (80mA∕mm, 35mS∕mm) gate dielectric.