Abstract
By employing plasma-assisted atomic layer deposition, thin films of Al2O3 and TiN are
subsequently deposited in a single reactor at a single substrate temperature with the objective of fabricating high-quality TiN/Al2O3 / p-Si metal-oxide-semiconductor capacitors. Transmission electron microscopy and Rutherford backscattering spectroscopy analyses show well-defined interfaces and good Al2O3 stoichiometry, respectively. Electrical investigation of as-deposited test structures demonstrates leakage current densities as low as ~1 nA/cm2. Current-voltage (I-V) measurements demonstrate clear Fowler–Nordheim tunneling with an average TiN/Al2O3 barrier
height of 3.3 eV. Steep Weibull distributions of the breakdown electric field around 7.5 MV/cm indicate good reliability of these devices. Time-dependent dielectric breakdown measurements demonstrate that the devices can sustain high operating electric fields of 3–4 MV/cm for the 10 year lifetime criterion. From capacitance-voltage (C-V) measurements, a dielectric constant (k) of 8.7± 0.1 was extracted for the Al2O3. No direct dependence on the deposition temperature was found in the range 350–400 °C, although the stack deposited at 400 °C demonstrates significantly lower C-V hysteresis of ~50 mV. A negative fixed oxide charge density of (9.6±0.2) x10 12 cm-2 was found to be present at the Al2O3 / p-Si interface. © 2009 American Institute of Physics.
Original language | English |
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Article number | 114107 |
Pages (from-to) | 114107-1/7 |
Number of pages | 7 |
Journal | Journal of Applied Physics |
Volume | 106 |
Issue number | 11 |
DOIs | |
Publication status | Published - 2009 |