Leakage Current Conduction Mechanisms Research Articles

Understanding the Charge Carrier Dynamics, Improved Dielectric Properties and Leakage Current Behaviour of NiFe1.85Dy0.15O4 with Structural Correlation

This research explores the charge carrier dynamics of NiFe1.85Dy0.15O4 with excess amounts of Dy ions replacing the metal ions and forming an additional orthorhombic phase of DyFeO3 confirmed by the X-ray diffraction pattern of the sample and validated by Scanning electron microscopy and UV-Visible studies. Dy incorporation, in conjunction with the additional phase, has been shown to alter the structure of the inverse spinel matrix by expanding the unit cell and inducing strain. Impedance spectroscopy was used to investigate the sample’s behaviour as a circuit element, and an equivalent circuit containing resistance, capacitance, and inductance was realized to represent the sample when exposed to an alternating field. The Cole-Cole model of non-Debye relaxation was used to calculate dielectric parameters such as dielectric strength, high-frequency permittivity, shape parameters, and dielectric relaxation times. The specimen’s leakage current conduction mechanism was also systematically investigated to determine the presence of different variants of bulk and interface-limited conduction processes. This multifaceted study not only reveals the intriguing charge dynamics of NiFe1.85Dy0.15O4, which are influenced by Dy-ion incorporation and the emergence of a new phase but also extends its implications to the realm of potential applications, spurring developments in areas like novel energy storage technologies and advanced electronics.

Interface Optimization and Performance Enhancement of Er2O3-Based MOS Devices by ALD-Derived Al2O3 Passivation Layers and Annealing Treatment.

In this paper, the effect of atomic layer deposition (ALD)-derived Al2O3 passivation layers and annealing temperatures on the interfacial chemistry and transport properties of sputtering-deposited Er2O3 high-k gate dielectrics on Si substrate has been investigated. X-ray photoelectron spectroscopy (XPS) analyses have showed that the ALD-derived Al2O3 passivation layer remarkably prevents the formation of the low-k hydroxides generated by moisture absorption of the gate oxide and greatly optimizes the gate dielectric properties. Electrical performance measurements of metal oxide semiconductor (MOS) capacitors with different gate stack order have revealed that the lowest leakage current density of 4.57 × 10-9 A/cm2 and the smallest interfacial density of states (Dit) of 2.38 × 1012 cm-2 eV-1 have been achieved in the Al2O3/Er2O3/Si MOS capacitor, which can be attributed to the optimized interface chemistry. Further electrical measurements of annealed Al2O3/Er2O3/Si gate stacks at 450 °C have demonstrated superior dielectric properties with a leakage current density of 1.38 × 10-9 A/cm2. At the same, the leakage current conduction mechanism of MOS devices under various stack structures is systematically investigated.

Comprehensive analysis of current leakage at individual screw and mixed threading dislocations in freestanding GaN substrates

The electrical characteristics of Schottky contacts on individual threading dislocations (TDs) with a screw-component in GaN substrates and the structures of these TDs were investigated to assess the effects of such defects on reverse leakage currents. Micrometer-scale platinum/GaN Schottky contacts were selectively fabricated on screw- and mixed-TD-related etch pits classified based on the pit size. Current–voltage (I–V) data acquired using conductive atomic force microscopy showed that very few of the screw TDs generated anomalously large reverse leakage currents. An analysis of the temperature dependence of the I–V characteristics established that the leakage current conduction mechanisms for the leaky screw TDs differed from those for the other screw and mixed TDs. Specifically, anomalous current leakage was generated by Poole–Frenkel emission and trap-assisted tunneling via distinctive trap states together with Fowler–Nordheim tunneling, with the mechanism changing according to variations in temperature and applied voltage. The leaky TDs were identified as Burgers vector b = 1c closed-core screw TDs having a helical morphology similar to that of other screw TDs generating small leakage currents. Based on the results, we proposed that the atomic-scale modification of the dislocation core structure related to interactions with point defects via dislocation climbing caused different leakage characteristics of the TDs.

Interface Chemistry and Defect State Optimization of the ErSmO/InP Heterojunction Modified by ALD-Driven Al2O3 Interlayers

In this work, the effects of the atomic-layer deposition (ALD)-derived Al2O3 passivation layer with different growth cycles on the interfacial chemistry and electrical performance of sputtering-driven ErSmO/InP metal oxide semiconductor (MOS) capacitors have been comparatively investigated. Atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) characterization have confirmed that the ALD-driven Al2O3 passivation layer with 20 growth cycles could form a flat dielectric layer and effectively suppress the diffusion of In and P elements at the InP interface. Meanwhile, the ErSmO/Al2O3/InP gate stack with 20 growth cycles exhibited optimal electrical properties, including a large dielectric constant of 37.42, a minimum interface state density (Dit) of 5.43 × 1011 eV–1 cm–2, and a low leakage current of 3.95 × 10–6 A/cm–2. The leakage current conduction mechanisms of InP-MOS capacitors measured at room temperature and low temperature have also been systematically analyzed. Particularly, low-frequency noise (LFN) is used to evaluate trap levels in InP-MOS capacitors. All experimental results have demonstrated that the ErSmO/Al2O3/InP gate stack has potential applications in future ultrahigh-speed and high-frequency microelectronic devices.

Interface engineering of p-type quaternary metal oxide semiconductor interlayer-embedded β-Ga2O3 Schottky barrier diode

Here, we propose a p-type copper aluminum oxide (p-CuAlO2) interlayer for the high breakdown and low leakage current of β-Ga2O3 Schottky barrier diodes (SBDs). The XPS and TEM analysis was employed to confirm the surface elemental compositions, chemical states, and microstructural properties of RF sputtered p-CuAlO2 thin films on β-Ga2O3. The electrical and carrier transport properties of Pt/β-Ga2O3 SBD and Pt/p-CuAlO2/β-Ga2O3 heterojunction (HJ) were studied by using current-voltage (I–V) and capacitance-voltage (C–V) measurements. In comparison to the SBD, the HJ displayed superior rectifying behavior, lower reverse leakage current, lower on-resistance, and a larger turn-on voltage. Higher barrier height (BH) was attained for the HJ compared to the SBD, which enabled the p-CuAlO2 interlayer to alter the barrier height. The reverse breakdown voltage of HJ increased by nearly 300 V compared to SBD and reached a maximum of 922 V. The BH values were extracted from the I–V, Hernandez, Cheung's, Mikhelashvili, Norde's, Chot, and surface potential methods found the values are comparable with one another, which indicates their steadiness and validity. The energy distribution profile of the interface state density (NSS) of the HJ decreases compared to the SBD, which indicates that the p-CuAlO2 interlayer facilitated the reduction of NSS of the Pt/β-Ga2O3 SBD interface. The forward log(I)-log(V) plot of the SBD and HJ reveals the ohmic nature at low voltage regions and space-charge limited conduction at higher voltage regions. Results reveal that the reverse leakage current conduction mechanism of the SBD and HJ showed that the Poole-Frenkel conduction mechanism is found to be governed in the lower voltage region, whereas the Schottky conduction mechanism is found to be directed in the higher voltage region, respectively. These outcomes point out that the p-CuAlO2 is a high potential candidate material for forming a heterojunction with β-Ga2O3.

Facile synthesis and characterizations of Co2+ doped Bi0.8Ba0.2FeO3 nano-crystalline multiferroic ceramics

Barium doped BiFeO3 and Cobalt doped Bi0.8Ba0.2FeO3 (BBFO) nanocrystalline multiferroic ceramics were prepared by the sol-gel technique. Rhombohedral symmetry was observed throughout the compositions, and the effect of sintering temperature was observed on volume and grain size of BBFO at (400 °C–700 °C) using x-ray profiles. The final sintering temperature for Cobalt doped (BBFCO) was estimated by using thermal analysis. DC I-V (current-voltage) analysis was used to analyze the leakage current density and conduction mechanism of ceramics. The temperature-dependent electrical resistivity measurements confirmed the metallic behaviour of Co2+ doped BBFO multiferroics at low temperatures, and transition temperature TMI was also found to be Cobalt concentration-dependent. The dielectric response, electrical impedance, and Modulus of the material were measured in the frequency range 100Hz to 2MHz at room temperature. Trends or occurrences may be attributed to oxygen vacancies arise due to doping content.

The Electrical Performances and Leakage Current Conduction Mechanism of Al2O3/ZrO2/SiO2/ZrO2/Al2O3 MIM Capacitors

In this paper, we prepared the Al2O3/ZrO2/SiO2/ZrO2/Al2O3 (AZSZA) metal-insulator-metal (MIM) capacitors by atomic-layer-deposition technique. By increasing the thickness of SiO2 from 0 nm to 3 nm, the quadratic capacitance voltage coefficients improved significantly from 2130 ppm/V2 to −121 ppm/V2 because of the offsetting effects of ZrO2 and SiO2 dielectric. Meanwhile, for our interested SiO2=3nm sample, the capacitance density is 7.40 fF/µm2 and the leakage current density is 3.08 × 10−8 A/cm2 at 5 V. We also studied the leakage current conduction mechanism of AZSZA dielectric MIM capacitors and found that at high field the conduction mechanism was dominated by Poole Frenkel emission.

Interface Optimization of Passivated Er2O3/Al2O3/InP MOS Capacitors and Modulation of Leakage Current Conduction Mechanism

The effect of atomic-layer-deposition (ALD)-derived Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> passivation layer on the interface quality of Er <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> /Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> /InP laminated stacks and the improvement of electrical performance has been investigated systematically. The chemical bonding states measured by high-resolution X-ray photoelectron spectroscopy (XPS) reveal that the ALD-derived Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> passivation layer can effectively inhibit the diffusion of substrate elements to optimize the interface quality. Electrical characterizations show that the optimized sample has demonstrated improved electrical properties, including the large dielectric constant of 20 and the suppressed leakage current density of 4.10×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-7</sup> cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . In addition, the leakage current conduction mechanisms are also investigated as a function of thickness of Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> passivation layer. The optimized interface state density extracted from the conductance method has reduced from 1.30 ×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sup> eV <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> of Er <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> /InP to 7.27 ×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sup> eV <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> of Er <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> /Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> /InP by adjusting the passivation layer thickness. As a result, it can be also confirmed that the passivation treatment is beneficial to inhibit the element's diffusion and optimize the interface quality, significantly controlling the capacitor degradation caused by the leakage current through the stacked oxide layer.

Temperature dependence of ferroelectric property and leakage mechanism in Mn-doped Pb(Zr0.3Ti0.7)O3 films

High-quality ferroelectric films of Mn-doped Pb(Zr0.3Ti0.7)O3 (PMZT) were prepared using the sol-gel method, and the temperature dependence of ferroelectric, dielectric, and leakage current properties (J–E) were explored in detail using the top electrode/ferroelectric films/bottom electrode capacitor heterostructure. The enhancement of polarization and dielectric properties by element doping is clearly observed by 3% Mn-doping. Such enhancement is beneficial for the application of these films in ferroelectric random-access memory. In addition, the analysis of leakage current reveals symmetric behavior with 3% Mn-doping and the leakage current density gradually increases with increasing temperature, which may be due to the movement of domain wall and oxygen vacancy. The dominant leakage current conduction mechanism is bulk-limited ohmic or interface-limited Schottky emission conduction within a wide temperature range. The results might be meaningful for further work on ferroelectric electrical devices with improved ferroelectric and dielectric properties.

Variation of leakage current conduction mechanism by heat treatment in Bi-based lead-free piezoelectric ceramics

The leakage current mechanism in the as-sintered and quenched 0.75BiFeO3–0.25BaTiO3 (0.75BF–0.25BT) ceramics is evaluated by the space-charge-limited current (SCLC), Poole–Frenkel (P–F) emission, Schottky (ST) emission, and Fowler–Nordheim (F–N) tunneling mechanism. The discrepancy observed in the optical dielectric constant of BF and BT between the reported value and the values calculated from the P–F and ST emission plots suggests that the P–F emission and ST emission mechanisms do not contribute to the leakage current behavior of the 0.75BF–0.25BT ceramics. Subsequently, F–N tunneling is observed under a high electric field in the as-sintered 0.75BF–0.25BT ceramics, whereas the direct tunneling effect is exhibited throughout the measured electric field in the quenched ceramics. The SCLC mechanism is dominant in both the as-sintered and quenched 0.75BF–0.25BT ceramics. A change from Ohmic conduction to trap-filled-limit conduction is observed with an increase in the applied electric field in the as-sintered ceramics, whereas the quenched ceramics only revealed Ohmic conduction over the entire range of the measured electric field. The different behaviors exhibited in the SCLC mechanism between the as-sintered and the quenched ceramics imply that the conduction mechanism can be controlled by heat treatment.

Electrical and carrier transport properties of Ti/α-amylase/p-InP MPS junction with a α-amylase polymer interlayer

This paper demonstrates the electrical and current transport properties of prepared Ti/α-amylase/p-InP metal/polymer/semiconductor (MPS) junction by current–voltage (I–V) approach. The microstructure of the fabricated MPS junction is confirmed by transmission electron microcopy (TEM) measurement. The MPS junction exhibited a good rectification nature over the Ti/p-InP metal/semiconductor (MS) junction. The derived barrier height (BH) of MPS junction (0.78 eV) is higher than the MS junction (0.70 eV), that indicates the BH is influenced by the polymer layer. The BH is extracted by the I–V, Z(V)–Vd plot, Cheung’s function, α(V)–V plot, Norde method and Ψs–V plot and found the values are comparable with one another, which indicates their steadiness and validity. The estimated interface state density (NSS) of the MPS junction is less than the MS junction, suggesting that the α-amylase layer decreased the NSS value. The forward log (I)–log (V) plot of the MS and MPS junctions reveals the ohmic nature at lower-bias region and space-charge-limited conduction at higher-bias region. Results reveal that the reverse leakage current conduction mechanism of the MS and MPS junctions is governed by Poole–Frenkel emission in lower-bias region, whereas, at higher bias region, Schottky emission is dominant current conduction mechanism. These exploration results establish that the α-amylase polymer layer is potential for use in organic–inorganic devices.

Interface Optimization and Modulation of Leakage Current Conduction Mechanism of Yb2O3/GaSb MOS Capacitors with ALD-Driven Laminated Interlayers

In this report, the impact of atomic-layer-deposition-derived different laminated gate stacks on the interface chemistry and electrical performance of Yb2O3/GaSb metal-oxide-semiconductor (MOS) cap...

Interface Optimization and Modulation of Leakage Current Conduction Mechanism of Yb2O3/GaSb MOS Capacitors With (NH4)2S Solutions Passivation

In current work, the impact of ammonium sulfide (NH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> ) <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> S solution passivation with varied pH value on the Yb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> /n-GaSb interface has been investigated comparatively. Compared with control samples, the neutral (NH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> ) <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> S solution passivation can effectively reduce oxides layer on GaSb surface and gate leakage via X-ray photoelectron spectroscopy(XPS) measurements and electrical characterization. High-low frequency capacitance method was used to evaluate interface-state density Dit, it was found that capping with Yb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> can delaythe interface-state generation and the lowest Dit value of 5.18 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sup> cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> eV <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> for Yb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> /GaSb capacitor with neutral (NH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> ) <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> S was achieved. Moreover, the possible leakage current conduction mechanisms for capacitors measured at room temperature and low temperature have also been discussed systematically.

Growth and Film Properties of Plasma-Enhanced and Thermal Atomic-Layer-Deposited Magnesium Oxide Films Using Bis(ethylcyclopentadienyl)Magnesium Precursor

As the device scaling of dynamic random access memory continues, the demand for the development of new dielectric film with high permittivity and low leakage current that may replace the currently used ZrO2/Al2O3-based dielectric film has increased drastically. In this aspect, MgO thin film has been spotlighted due to its high band gap (7-8 eV) and moderate dielectric constant (9-10).In this study, we investigated the growth behavior and film properties of the MgO ALD film using Mg(EtCp)2 precursor and the different reactants of H2O and O2 plasma. MgO thin films were deposited at the temperature range of 200-400°C, and the self-limited surface reaction was observed to secure optimal growth conditions. Glancing angle X-ray diffraction and X-ray photoelectron spectroscopy were used to examine crystalline structure and chemical properties, respectively. To evaluate the electrical characteristics of the MgO films, the Pt/MgO/TiN capacitor was fabricated with different MgO thicknesses at various deposition temperatures. The electrical characteristics such as dielectric constant and leakage current density of the MgO film were examined depending on the reactants, and the leakage current conduction mechanism of the MgO thin films was elucidated. Figure 1

Conduction mechanisms of oxide leakage current in p-channel 4H-SiC MOSFETs

Electron and hole leakage current conduction mechanisms under a negative gate bias condition in p-channel 4H-SiC MOSFETs were investigated. Electron leakage current from the gate electrode side was dominant when the gate electrode was n+ poly Si. From the temperature dependence, it was found that the conduction mechanism consists of the Fowler–Nordheim (FN) and the Pool–Frenkel (PF) mechanisms. On the other hand, analysis of hole leakage current was impeded by hot electrons injected from the gate electrode side. To suppress electron injection, Ni was used as a gate electrode. With the Ni-gate MOSFETs, electron injection was suppressed, and it was possible to analyze the hole leakage current mechanism. The analysis revealed that the hole leakage current also consists of both the FN and PF mechanisms. This study reveals that it is important to select an appropriate gate electrode material when applying a high negative gate bias for 4H-SiC MOSFETs.

Modulation of the microstructure, optical and electrical properties of sputtering-driven Yb2O3 gate dielectrics by sputtering power and annealing treatment

The effect of sputtering power and annealing temperature on the microstructure, optical and electrical properties of sputtering-derived Yb2O3 high-k gate dielectrics on Si substrate have been investigated systematically. Based on measurements by ultraviolet-visible spectroscope (UV-Vis) and spectroscopic ellipsometry (SE), the increase in band gap and reduction in refractive index have been detected. Structural analyses by x-ray diffraction (XRD) reveal that the Yb2O3 thin films exhibit a cubic phase at higher annealing temperature. X-ray photoelectron spectroscopy (XPS) analyses demonstrate the decreased Yb silicate and low-k SiO2 interfacial layer for the samples annealed at 300 °C. Electrical measurements have indicated that Yb2O3/Si gate stacks annealed at 300 °C shows excellent dielectric performance with leakage current density of 3.66 × 10−8 A/cm2 at applied voltage of 1 V. As a supplement, the leakage current conduction mechanisms of MOS capacitor for different annealing temperature have been discussed systematically.

Growth characteristics and film properties of plasma-enhanced and thermal atomic-layer-deposited magnesium oxide thin films prepared using bis(ethylcyclopentadienyl)magnesium precursor

The continuous device scaling of dynamic random access memories has been increasing demands for the development of dielectric materials with high dielectric constants and low leakage currents. In this study, we developed MgO thin films through atomic layer deposition (ALD) using bis(ethylcyclopentadienyl)magnesium combined with two different reactants, H2O or O2 plasma, and compared the physical and chemical characteristics of MgO thin films produced by thermal ALD (Th-ALD) and plasma-enhanced ALD (PEALD). The films were deposited in a temperature range of 200–400 °C, and self-limited surface reactions were observed for both ALD processes. Th-ALD MgO films showed the oxygen deficient composition, while more stoichiometric MgO films were achieved by PEALD process. To evaluate the electrical characteristics of the MgO films, the metal–insulator–metal capacitors were fabricated. The electrical characteristics of the MgO film, such as the dielectric constant and leakage current, were compared according to the reactant type. The bulk-limited leakage current conduction mechanisms of the Th-ALD and PEALD MgO thin films were also investigated.

Structural, electrical, and optical properties of polycrystalline (1−x)BiFeO3-xBi0.5K0.5TiO3 thin films

The effects of multiferroic (1 − x)BiFeO3-xBi0.5K0.5TiO3 (BFO-xBKT, x = 0, 0.1, 0.2, 0.3, and 0.4) thin films on the structural, electrical, and optical properties had been investigated. The phases of all the films corresponded to a perovskite structure according to the X-ray diffraction patterns and the Raman shift measurements. Meanwhile, the merging of (104) and (110) peaks of the BFO-xBKT thin films revealed the phase transition from a rhombohedral structure to a tetragonal structure. The atomic force microscope showed that the BFO-xBKT thin films had uniform morphology and the grain size of the BFO-xBKT thin films became smaller when the Bi0.5K0.5TiO3 content increased. The maximum remnant polarization 2Pr = 17.1 μC/cm2 and lowest leakage current of 3.07×10−7 A/cm2 were observed in the BFO−0.3BKT thin film. The leakage current conduction mechanism displayed Ohmic conduction in the low electric field region and in the high electric field region, the mechanism was dominated by the Fowler−Nordheim tunneling for BFO-xBKT (x = 0.1, 0.2, 0.3, and 0.4) thin films. The absorption edges of BFO-xBKT were blue-shifted with the increasing of the x value.

Atomic-layer-deposited (ALD) Al2O3 passivation dependent interface chemistry, band alignment and electrical properties of HfYO/Si gate stacks

In this work, the effects of atomic-layer-deposited (ALD) Al2O3 passivation layers with different thicknesses on the interface chemistry and electrical properties of sputtering-derived HfYO gate dielectrics on Si substrates have been investigated. The results of electrical measurements and X-ray photoelectron sepectroscopy (XPS) showed that 1-nm-thick Al2O3 passivation layer is optimized to obtain excellent electrical and interfacial properties for HfYO/Si gate stack. Then, the metal-oxide-semiconductor capacitors with HfYO/1-nm Al2O3/Si/Al gate stack were fabricated and annealed at different temperatures in forming gas (95% N2+5% H2). Capacitance-voltage (C-V) and current density-voltage (J-V) characteristics showed that the 250 °C-annealed HYO high-k gate dielectric thin film demonstrated the lowest border trapped oxide charge density (-3.3 × 1010 cm−2), smallest gate-leakage current (2.45 × 10-6 A/cm2 at 2 V) compared with other samples. Moreover, the annealing temperature dependent leakage current conduction mechanism for Al/HfYO/Al2O3/Si/Al MOS capacitor has been investigated systematically. Detailed electrical measurements reveal that Poole-Frenkle emission is the main dominant emission in the region of low and medium electric fields while direct tunneling is dominant conduction mechanism at high electric fields.

Growth assessment and scrutinize dielectric reliability of c-axis oriented insulating AlN thin films in MIM structures for microelectronics applications

The present study reports the effect of bottom electrodes (Al, Pt & Ti) on the texture, piezoelectric characteristics, dielectric properties and leakage current behavior of reactive DC magnetron sputtered AlN thin films. X-ray diffraction results revealed that the lattice structure and texture of bottom electrode plays a vital role in c-axis wurtzite phase growth of aluminum nitride (AlN) thin films. A highly (002) oriented c-axis AlN thin films was obtained over Ti as compared to Al and Pt electrodes. The piezoelectric coefficient (d33eff) of these fabricated AlN thin films were measured by piezoresponse force microscopy to evaluate their piezoelectric efficiency in resonators. AlN is a good option for passivation purpose in microelectronic devices because of high chemical stability and excellent dielectric properties. Therefore, the dielectric reliability of AlN thin films is very crucial. Among all structures, AlN/Ti structure exhibits a highest dielectric constant (εr) ∼ 8.63 at 1 MHz. This work also provided a comprehensive study of leakage current conduction mechanism with electric field. The leakage behavior depicts that all AlN film endures a transition from ohmic conduction (E < 70 kV/cm) to SCLC conduction (E > 70 kV/cm). In addition, the breakdown characteristic of these fabricated films was studied for deciding the long-term device reliability and life. This study suggests that the electrode engineering of AlN thin films have a potential in devices for electrical and micro-electro-mechanical system (MEMS) applications.