Investigation of atomic layer deposited beryllium oxide material properties for high-k dielectric applications

Beryllium oxide (BeO) is a wide band gap alkaline earth oxide material that has recently shown significant promise as a high-k dielectric material in Si and III-V metal–oxide–semiconductor field effect transistor devices. However, many of the basic material properties for BeO thin films utilized in these devices have not been reported or remain in question. In this regard, the authors report an investigation of the chemical, physical, electrical, and mechanical properties of BeO thin films formed via atomic layer deposition (ALD). Combined Rutherford backscattering and nuclear reaction analysis measurements show that ALD BeO thin films exhibit a low hydrogen content (<5%) and are nearly stoichiometric (Be/O ≅ 1.1 ± 0.05). Reflection electron energy loss spectroscopy measurements reveal a wide band gap of 8.0 ± 0.14 eV, and nanoindentation measurements show that ALD BeO has a high Young's modulus and hardness of 330 ± 30 and 33 ± 5 GPa, respectively.