A parameterized, Kramers–Kronig consistent, Cody–Lorentz optical model is used to simulate the dielectric response of thin HfxSiyOz films. Optical constants are determined in the range 0.75–8.35eV. The Cody–Lorentz model has three specific differences when compared to the previously employed Tauc–Lorentz model: (1) weak exponential absorption below the band gap, (2) a modified joint density-of-states, and (3) a restriction on the ε1(∞) parameter. These three differences allow the Cody–Lorentz model to have an improved fit to experimental data. As a result of a more accurate optical model for HfxSiyOz, we were able to identify an interfacial layer with thickness in close agreement with transmission electron microscopy measurements. Use of the Tauc–Lorentz model when fitting the same experimental data could not identify an interfacial layer. Results are also discussed in which the Cody–Lorentz model shows sensitivity to varying degrees of silicate composition.

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As complementary metal oxide semiconductor devices continue to scale along the rapid pace of Moore's law, gate dielectric materials with significantly higher dielectric constant ͑k =10-25͒ are being evaluated as replacements for conventional silicon dioxide, SiO 2 ͑k = 3.9͒, and silicon oxynitride. This allows for the introduction of a physically thicker film with lower leakage current and with capacitance equivalent to a thinner ͑1.0 nm and below͒ SiO 2 layer ͑Schlom and Haeni, 2002;Wilk et al., 2001;Kingon et al., 2001͒. Although binary metal oxide films such as HfO 2 and ZrO 2 exhibit higher permittivity than their corresponding silicates and aluminates, alloyed with various molecular percents of SiO 2 or Al 2 O 3 , respectively, they are compromised by lower onset of crystallization temperature which contributes a higher degree of interfacial microroughness and increased gate leakage current due to dislocations and oxygen vacancies generated along grain boundaries. Accordingly, development of hafnium silicate has been the subject of intense investigation as an advanced gate dielectric thin film designed to meet the device manufacturing requirements of thermal stability in direct contact with substrate silicon and metal gate electrode materials. In this paper, we present results corresponding to the utilization of total reflection X-ray fluorescence spectroscopy ͑TXRF͒ as a quick, accurate, nondestructive technique for hafnium silicate composition determination based on detection of the Hf:Si ratio of ͑HfO 2 ͒ x ͑SiO 2 ͒ 1−x , where x varies over the range 0.2-1.0. © 2005 International Centre for Diffraction Data.

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to HfOz. Fig. 5 shows the Ig-Vg characteristics in both accumulation A fabrication process for HfON using ion implantation of and inversion regimes for HfON and Hf02 devices. Although HfON NZ in ALD Hf02 was demonstrated. Results showed that a good shows -1A less EOT than HfOZ, HfON still has less gate leakage quality HfON could he formed by Nz implantation, which suggests than HfOz. The gate leakage reduction evaluated at Vi%-1 is 69% nitrogen implantation can he an alternative high-k niaidation (NMOS) and at Vfb+l is 25% (PMOS). Fig. 6 shows the mobility technique. This process was successfully integrated into a traditional extraction for both NMOS and PMOS using the NCSU routine [3]. CMOS flow and the electrical and reliability results of HfON, as Even with the presence of N in the HfON film, both the electron and compared to Hf02, showed IO times less Vt shift in the pulsed Id-Vg hole mobility still perform better than HfO?. TDDB testing results measurement and up to 70% gate leakage reduction. In addition, (-60 to 70 DUTs per data point) is shown in Fig. 7 where HfON EOT, electrodhole mobility, TDDB and subthreshold slope of HfON performs better than Hf02 in terms of E-field. We used the pulsed also were performed better than those of HfOZ. A model is proposed Id-Vg technique 141 (Fig. 8) to evaluate the electrical stability of to explain the result by attributing the improvement to the reduction HfON and HfOz and the result is shown in Fig. 9 where an order of of defect states (oxygen vacancies) in the Hf02 film by the presence magnitude of improvement was observed in HfON as compared to of N in the HfON film.HfOz film.