Determination of electron effective mass and electron affinity in HfO2 using MOS and MOSFET structures

Abstract

We present a combined electrical and modeling study to determine the tunneling electron effective mass and electron affinity for HfO 2 . Experimental capacitance-voltage (C-V) and current-voltage (I-V) characteristics are presented for HfO 2 films deposited on Si(100) substrates by atomic layer deposition (ALD) and by electron beam evaporation (e-beam), with equivalent oxide thicknesses in the range 10-12.5 Å. We extend on previous studies by applying a self-consistent 1D-Schrödinger-Poisson solver to the entire gate stack, including the inter-layer SiO x region -and to the adjacent substrate for non-local barrier tunnellingself-consistently linked to the quantum-drift-diffusion transport model. Reverse modeling is applied to the correlated gate and drain currents in long channel MOSFET structures. Values of (0.11 ± 0.03)m o and (2.0 ± 0.25) eV are determined for the HfO 2 electron effective mass and the HfO 2 electron affinity, respectively. We apply our extracted electron effective mass and electron affinity to predict leakage current densities in future 32 nm and 22 nm technology node MOSFETs with SiO x thicknesses of 7-8 Å and HfO 2 thicknesses of 23-24 Å.

Observation of peripheral charge induced low frequency capacitance-voltage behaviour in metal-oxide-semiconductor capacitors on Si and GaAs substrates

“…It is possible that the 900 C RTA step performed on the exposed GdSiO x surface resulted in residual negative charge due to moisture reactions on the GdSiO x surface. Similar behaviour has been reported previously on n-type Si with a HfO 2 dielectric which was exposed during MOS device processing, 20,28 and in the case of the study by O'Sullivan et al, the corresponding p-type devices did not exhibit any inversion behaviour. 20 Significantly, the inversion response on the TiN/GdSiO x /n-Si devices in the present work is gate area dependent, as is expected in the presence of peripheral charge.…”

Electronic structure, effective masses, mechanical and thermo‐acoustic properties of cubic HfO2 under pressure

“…We can see decreasing effective masses versus pressure due to the increase of the energy levels. Experimental value for electron effective mass is m à e ¼ (0.11 AE 0.03)m 0 for the ebeam and ALD-deposited HfO 2 films [22]; our results are heavier than the experimental value, but our values are in agreement with the previous work [9], and the calculated values for cubic HfO 2 will help to study the advanced metaloxide-semiconductor devices in microelectronic devices.…”

On the Oxide Trap Density and Profiles of 1-nm EOT Metal-Gate Last CMOS Transistors Assessed by Low-Frequency Noise

“…One comment which is at its place here is that there exists a wide range of values for the electron affinity between 1.75 and 2.82 eV and the electron tunneling effective mass (0.08 to 0.4 m 0 ; m 0 is the rest mass of the electron) in HfO 2 [41]- [44]. According to (2), this also gives rise to a range of values for the attenuation factor α t between 5 × 10 7 cm −1 and ∼1 ×10 8 cm −1 .…”