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In this work, the physical and electrical properties of SrxTi1-xOy (STO)-based metal-insulator-metal capacitors (MIMcaps) with various compositions are studied in detail. While most recent studies on STO were done on noblelike metal electrodes (Ru, Pt), this work focuses on a low temperature (250 °C) atomic layer deposition (ALD) process, using an alternative precursor set and carefully optimized processing conditions, enabling the use of low-cost, manufacturable-friendly TiN electrodes. Physical analyses show that the film crystallization temperature, its texture and morphology strongly depends on the Sr/Ti ratio. Such physical variations have a direct impact on the electric properties of SrxTi1-xOy based capacitors. It is found that Sr-enrichment result in a monotonous decrease in the dielectric constant and leakage current as predicted by ab initio calculations. The intercept of the EOT vs physical thickness plot further indicates that increasing the Sr-content at the film interface with the bottom TiN would result in lower interfacial equivalent-oxide thickness. [ABSTRACT FROM AUTHOR]

The physical and electrical properties of [Sr.sub.x][Ti.sub.1-x][O.sub.y] (STO)-based metal-insulator-metal capacitors (MIMcaps) with various compositions are analyzed. The intercept of EOT vs physical thickness plot has shown that increasing the Sr-content at the film interface with the bottom TiN has resulted in lower interfacial equivalent-oxide thickness.

The Si dangling bond interface defects are probed by electron spin resonance in entities of (100)Si with ultrathin SiO2 grown in Ozonated de-ionized water solution at room temperature. Standard quality thermal Si/SiO2 interface properties are not obtained by oxidation in ozonated water solutions at room temperature, which can be upgraded by providing additional thermal budget.

Si dangling bond interface defects (P[sub b0],P[sub b1]) were probed by electron spin resonance in entities of (100)Si with ultrathin SiO[sub 2] grown in ozonated de-ionized water solution at room temperature. After photodesorption of passivating hydrogen, P[sub b0] appears with densities up to ∼ 5 × 10[sup 12] cm[sup -2], a value five times larger than the one standardly attained with high temperature thermal growth. Thus standard quality thermal Si/SiO[sub 2] interface properties, as exposed by the P[sub b0]-type defects criterion (interface traps), are not obtained by oxidation in ozonated water solutions at room temperature. The interface quality may be upgraded by providing additional thermal budget. Yet standard qualitity is still not attained after vacuum annealing at 600°C. [ABSTRACT FROM AUTHOR]

Plasma-assisted atomic layer deposition (ALD) was used to deposit SiO2 films in the temperature range of Tdep = 50-400°C on Si(100). H2Si[N(C2H5)2]2 and an O2 plasma were used as Si precursor and oxidant, respectively. The ALD growth process and material properties were characterized in detail. Ultrashort precursor doses (∼50 ms) were found to be sufficient to reach self-limiting ALD growth with a growth-per-cycle of ∼1.2 Å (Tdep = ∼200°C) leading to SiO2 films with O/Si ratio of ∼2.1. Moreover, the plasma ALD process led to a high conformality (95-100%) for trenches with aspect ratios of ∼30. In addition, the electronic (interface) properties of ultrathin ALD SiO2 films and ALD SiO2/Al2O3 stacks were studied by capacitance-voltage and photoconductance decay measurements. The interface quality associated with SiO2 was improved significantly by using an ultrathin ALD Al2O3 capping layer and annealing. The interface defect densities decreased from ∼1×1012 eV-1 cm-2 (at mid gap) for single layer SiO2 to < 1011 eV-1 cm-2 for the stacks. Correspondingly, ultralow surface recombination velocities < 3 cm/s were obtained for n-type Si. The density and polarity of the fixed charges associated with the stacks were found to be critically dependent on the SiO2 thickness (1-30 nm). [ABSTRACT FROM AUTHOR]

GdxHf1-xOy. thin films were deposited by atomic layer deposition (ALD) using tris(isopropyl-cyclopentadienyl) gadolinium [Gd(PrCp)3] and HfCI4 in combination with H2O as an oxidizer. Growth curves showed a nearly ideal ALD behavior. The growth per individual Gd(iPrCp)3/H2O or HfCI4/H2O cycle was 0.55 A, independent of the Gd/(Gd + Hf) composition x in the studied range. This indicates that the amount of HfO2 deposited during a HfCI4/H2O cycle was essentially identical to the amount of Gd2O3 deposited during a Gd(iPrCp)3/H2O cycle, assuming identical atomic densities of the films independent of composition. The crystallization of GdxHf1-xOy with Gd/(Gd + Hf) contents x between 7 and 30% was studied. Films with x ⩾10% crystallized into a cubic/tetragonal HfO2-like phase during spike or laser annealing up to 1300°C, demonstrating that the cubic/tetragonal phase is thermally stable in this temperature range. A maximum dielectric constant of K∼ 36 was found for a Gd/(Gd + Hf) concentration of x 11%. [ABSTRACT FROM AUTHOR]

Strontium titanate (STO) is a promising candidate as a highk dielectric for dynamic random access memory application. STO thin films are deposited by atomic layer deposition using Sr(tBu3Cp)2, Ti(OMe)4, and H2O as precursors. Growth and saturation behavior of STO and binary oxides are evaluated by ellipsometry thickness measurements. The precursor pulse ratio controls the amount of Sr and Ti inëorporated in STO films. Stoichiometric SrTiO3 is characterized by the lowest crystallization temperature and largest refractive index, density, and dielectric constant. An excess of Ti or Sr results in an increase in the crystallization onset temperature and contraction or expansion of the cubic cell constant of perovskite SrTiO3. Incorporation of more Sr in STO reduces the leakage current density but also increases the capacitanceequivalent thickness. [ABSTRACT FROM AUTHOR]

Although the next generation high-k gate dielectrics has been defined for the 45 nm complementary metal oxide semiconductor technology node, threshold voltage control and equivalent oxide thickness (EOT) scaling remain concerns for future devices. Therefore, the authors explored the effect of incorporating dysprosium in the gate stack. Results suggest that improved EOT-leakage scaling is possible by adding Dy to the interfacial SiO2 layer in a 1:1 ratio or by adding 10% Dy to bulk HfO2. The deposition of a 1 nm Dy2O3 cap layer lowered the threshold voltage by ∼250 mV. In addition, for future dynamic random access memory capacitor applications, dielectrics with [variant_greek_epsilon] of 50–130 are projected by the International Technology Roadmap for Semiconductors, unachievable with standard high-k dielectrics. Theoretical modeling can help direct the experimental work needed for extensive screening of alternative dielectrics. Moreover, materials such as perovskites only exhibit a sufficiently high-k value when properly crystallized. Therefore, control over the crystalline phase of the material might become a necessity to obtain the proper material characteristics as shown for SrTiOx. After crystallization, the permittivity was observed to increase from 20 to 135. In addition, material and gate stack optimization to limit leakage current densities for these higher-k dielectrics will be needed. [ABSTRACT FROM AUTHOR]

An electron spin resonance study has been carried out on the effect of in situ applied in-plane stress to (1 1 1)Si substrates during oxidation on the formation of inherent Pb (Si3&z.tbnd6;Si⋅; Si dangling bond) interface defects in (1 1 1)Si/SiO2. Analysis for various, both compressive and tensile, stress levels reveals the properties of these electrically active point defects to be significantly affected, in particular their incorporated inherent density and signal shape. Interestingly, the inherent Pb density is reduced by applied tensile stress, with an opposite result for compressive. The data support the commonly accepted relationship between inherent incorporation of the Pb defects and Si/SiO2 interface mismatch. [Copyright &y& Elsevier]

The structural degradation of thermal SiO 2 on (1 0 0)Si under isochronal post oxidation vacuum annealing (POVA) has been probed by electron spin resonance (ESR). The degradation process, studied in the range T an  = 950-1250 °C, is established as intense point defect generation including E ′ γ , E ′ δ , EX and the elusive predominant degradation center S . Thermally activated generation is revealed over broad T an ranges for the two most populous defects, S and E ′ γ , with a common activation energy ∼1.6 eV. Depth profiling after heating at 1200 °C shows that the S centers predominantly reside near the oxide borders, generally in anticorrelation with the E ′ γ distribution. The S center susceptibility has been inferred from conventional ESR signal intensity monitoring as well as from revealed anisotropic demagnetisation effects. It is found Curie-Weiss type with critical temperature of ∼1.3 K. Newly observed weak hyperfine structure may comply with the S center being an E ′-like defect. [ABSTRACT FROM AUTHOR]

The results of a series of experiments are reported in which constant, controlled levels of in-plane stress were applied in sim to oxidizing (111) silicon substrates. Electron spin resonance measurements show that the properties of inherently incorporated electrically active P[sub b] defects at the (111)Si/SiO[sub 2] interface are affected; among others, tensile stresses decrease the number of P[sub b]s, while compressive stresses have the opposite effect. The results are in agreement with the generally accepted relationship between P[sub b]-defect generation and interfacial mismatch (stress). [ABSTRACT FROM AUTHOR]

The structural degradation of thermal SiO[sub 2] on (100)Si under isochronal vacuum annealing in the range T[sub an] = 950 °C-1250 °C was monitored by electron spin resonance (ESR) in terms of point defect creation, including E′[sub γ], E′[sub δ], EX and the elusive predominant degradation-center S. Depth profiling after heating at 1200 °C shows that the S centers predominantly reside near the oxide borders, generally in anticorrelation with the E′[sub γ] distribution. The resulting anisotropic demagnetization effect has enabled inference of the S center susceptibility. As to the nature of the S center, an observed weak hyperfine structure may comply with the S center being of the type Si[sub n]O[sub 3-n]≡Si[sup ·] either the single n = 1 or a mix of both the n = 1,2 variants. [ABSTRACT FROM AUTHOR]

Abstract: A first-principles Density Functional Theory (DFT) approach was employed to predict the effective charges, phonon modes, band-gap and dielectric constant of a series of Sr-rich SrTiO3. The fabricated MIM capacitors confirm the theoretical trends obtained for the dielectric constants, the later showing a possible upper limit of the dielectric response. [Copyright &y& Elsevier]