Metal Insulator Semiconductor Capacitors Research Articles

Comparative study of the interface passivation properties of LiF and Al2O3 using silicon MIS capacitor

Lithium fluoride (LiF) is currently a very popular dielectric material used as a passivation or transport layer in a variety of applications, especially in high-efficiency solar cells. Despite this, its conduction properties and interface behavior with silicon remain largely unexplored. In this work, a LiF metal–insulator–semiconductor (MIS) structure is fabricated and characterized, and its properties are compared to the well-understood aluminum oxide (Al2O3) MIS structure. First, a higher current density in LiF compared to Al2O3 is highlighted, as well as its PN junction-like behavior with n-type silicon (n-Si), being rather unconventional for a dielectric layer. C–V measurements showcase the likely presence of an interface defect, causing an increase in the apparent doping and a shift in the flatband voltage VFB by +70 meV. This defect is found to be of the acceptor type, which renders the interface fixed charge more negative and improves the field-effect passivation in the case of a negative Qf. Finally, a density of interface states Dit≈2×1011 cm−2 eV−1 was found for LiF/n-Si, which is a low value showing appropriate chemical passivation at the interface. Overall, this work enables us to shed more light on the interface properties of LiF on n-Si, which is an essential step toward its wider use in state-of-the-art solar cells and other silicon-based devices.

Optimizing the Crystallinity of a ZrO2 Thin Film Insulator for InGaZnO‐Based Metal–Insulator–Semiconductor Capacitors

AbstractThe utilization of a zirconium oxide (ZrO2) thin film as the insulator in a metal–insulator–semiconductor (MIS) capacitor to enhance the characteristics of thin‐film transistors is investigated. Although the high crystallinity of ZrO2 is favorable to achieving higher capacitance density in metal–insulator–metal capacitors with ZrO2 thin films, it decreases the capacitance with increasing applied bias in Mo/ZrO2/InGaZnO (IGZO)‐structured MIS capacitors. Through comprehensive physical, chemical, and electrical characterizations, this study investigated the mechanism underlying the decreasing capacitance with increasing the applied bias in the accumulation state of the Mo/ZrO2/IGZO‐structured MIS capacitor depending on the crystallinity of ZrO2. Furthermore, the investigation identifies the optimal crystal structure of ZrO2 thin films for IGZO‐based MIS capacitors, highlighting the importance of forming meso‐crystalline structures in high dielectric constant (k) materials to enhance the k value and mitigating the decrease in capacitance caused by the accumulated carrier loss through grain boundaries of ZrO2.

Preparation of Remote Plasma Atomic Layer-Deposited HfO2 Thin Films with High Charge Trapping Densities and Their Application in Nonvolatile Memory Devices.

Optimization of equipment structure and process conditions is essential to obtain thin films with the required properties, such as film thickness, trapped charge density, leakage current, and memory characteristics, that ensure reliability of the corresponding device. In this study, we fabricated metal-insulator-semiconductor (MIS) structure capacitors using HfO2 thin films separately deposited by remote plasma (RP) atomic layer deposition (ALD) and direct-plasma (DP) ALD and determined the optimal process temperature by measuring the leakage current and breakdown strength as functions of process temperature. Additionally, we analyzed the effects of the plasma application method on the charge trapping properties of HfO2 thin films and properties of the interface between Si and HfO2. Subsequently, we synthesized charge-trapping memory (CTM) devices utilizing the deposited thin films as charge-trapping layers (CTLs) and evaluated their memory properties. The results indicated excellent memory window characteristics of the RP-HfO2 MIS capacitors compared to those of the DP-HfO2 MIS capacitors. Moreover, the memory characteristics of the RP-HfO2 CTM devices were outstanding as compared to those of the DP-HfO2 CTM devices. In conclusion, the methodology proposed herein can be useful for future implementations of multiple levels of charge-storage nonvolatile memories or synaptic devices that require many states.

Pulsed laser deposited Dy and Ta doped hafnium- zirconium oxide thin films for the high-k applications

Hf0.6Zr0.2Dy0.1Ta0.1O2 thin films were deposited on Si (100) at 600°C using pulsed laser deposition for gate oxide applications because of the compatibility of the elements with the CMOS process. Special emphasis was placed on the properties of Hf0.6Zr0.2Dy0.1Ta0.1O2 thin films within metal-insulator-semiconductor (MIS) structure (Pt/Hf0.6Zr0.2Dy0.1Ta0.1O2/Si) for high-k application in logic devices. The capacitance-voltage and current-voltage measurements are used to determine the electrical characteristics of MIS capacitor structures. The minimum equivalent oxide thickness and maximum dielectric constant of the thin films obtained were as low as 1.2 nm and as high as 35.7 at 10 kHz, respectively. Results on the gate stacks obtained based on the MIS structures appear to be promising as the high-k material for logic devices.

Fabrication of metal/oxide/fluorographene/oxide/silicon capacitors and their charge trapping properties

Graphene is well-known as a material with extremely high carrier mobility, although its electrical properties can be changed into those of a highly insulating thin film by a fluorination treatment (fluorographene). Taking advantage of this property, a flexible nonvolatile memory using fluorographene as a charge trapping layer has been proposed. However, the mechanism of charge trapping on fluorographene is not yet fully understood. In this paper, we fabricated fluorographene and analyzed it by X-ray photoelectron spectroscopy and Raman spectroscopy. Furthermore, metal–insulator–semiconductor (MIS) capacitors inserted with fluorographene were fabricated and evaluated electrically. As a result, a large flat-band voltage shift was observed even though the fluorine concentration (C–F bonding ratio) was saturated at around 14%. Furthermore, the charge centroid of the MIS capacitor with fluorographene coincides with the location of the fluorographene. These results indicate that fluorographene can capture injected charges and is a candidate for use in nonvolatile memory with two-dimensional materials.

Physical and Chemical Interactions of the Polar and Nonpolar Solvents on the Mesoporous Silica Material to Developing Solvent Sensors.

AbstractThis work examines the physical and chemical interactions between the polar and nonpolar solvents and the surface of the MCM‐41 material, which serves as the isolating layer, employing sensing capacitance‐voltage measurements with a Metal‐Insulator‐Semiconductor (MIS) capacitor. It was observed that the MCM‐41 surface is more sensitive to methanol, which is a protic solvent, than to other nonpolar solvents like chloroform, according to the data. Furthermore, by analyzing the interaction of the methanol with the surface of MCM‐41 as a function of the applied field, the electron transfer, and the orientation of the solvent molecule, DFT Calculations using the Siesta simulation software enable us to assess this sensitivity. Based on the performance of MCM‐41 as the insulator in the MIS capacitor, MCM‐41 has a strong potential for the creation of high‐sensitivity sensors for solvent detection avoiding the functionalization process.

Reliability Characteristics of Metal-Insulator-Semiconductor Capacitors with Low-Dielectric-Constant Materials.

In this study, the reliability characteristics of metal-insulator-semiconductor (MIS) capacitor structures with low-dielectric-constant (low-k) materials have been investigated in terms of metal gate area and geometry and thickness of dielectric film effects. Two low-k materials, dense and porous low-k films, were used. Experimental results indicated that the porous low-k films had shorter breakdown times, lower Weibull slope parameters and electric field acceleration factors, and weaker thickness-dependence breakdowns compared to the dense low-k films. Additionally, a larger derivation in dielectric breakdown projection model and a single Weilbull plot of the breakdown time distributions from various areas merging was observed. This study also pointed out that the porous low-k film in the irregular-shaped metal gate MIS capacitor had a larger dielectric breakdown time than that in the square- and circle-shaped samples, which violates the trend of the sustained electric field. As a result, another breakdown mechanism exists in the irregular-shaped sample, which is required to explore in the future work.

Capacitance–voltage characterization of metal–insulator–semiconductor capacitors formed on wide-bandgap semiconductors with deep dopants such as diamond

As diamond possesses only deep dopants, certain conventional physics and characterization methods are not applicable to diamond devices, owing to the explicit or implicit assumption of shallow dopants. To resolve this limitation, the capacitance–voltage (C–V) characteristics of metal–insulator–semiconductor (MIS) capacitors formed on a semiconductor substrate with deep and compensating dopants were successfully formulated. Based on these equations, methods for accurately estimating the MIS capacitor properties were developed and validated through their application in the analysis of an actual MIS capacitor formed on a boron-doped hydrogen-terminated diamond substrate. The high-frequency C–V characteristic of the capacitor exhibited a prominent dip specific to deep dopants. However, the dip depth was considerably shallower than theoretically expected. This C–V characteristic was accurately reproduced theoretically, assuming the presence of a surficial diamond layer that contains acceptors with an activation energy of 0.23 eV, which is less than the value 0.37 eV for boron, and has a thickness of the extrinsic Debye length (40 nm in this study) or larger. The insulator charge of the MIS capacitor was estimated as −4.6 × 1012 cm−2 in units of electronic charge, which is sufficiently large to induce two-dimensional hole gas. The interface-state density was 1.4 × 1012 cm−2 eV−1 for interface-state energies of 0.3–0.5 eV above the valence band maximum. Hence, the proposed methodology and the possible presence of the reduced activation energy layer will guide the development of diamond-based devices.

Channel characteristics of ferroelectric organic High-K dielectric asymmetric metal insulator semiconductor capacitor

In the present work, it is demonstrated that an asymmetric organic MIS (AMIS) capacitor utilizing sandwiched ferroelectric material between high k-dielectric as an insulator and pentacene as an active semiconductor can be used for a wide range of sensing applications. The capacitive test structure is simpler in fabrication and characterization and is less sensitive to defect states since it utilizes a strong accumulation region. The polarization behavior of the ferroelectric materials enables higher charge density in the channel thereby reducing channel resistance and thus increasing the channel capacitance. This property of the Ferro-based AMIS structure enables the extraction of OTFT parameters and also serves as a platform for sensing applications. The use of high-k dielectric material both as an insulator and buffer layer makes the technique more robust against lattice mismatch and high-power dissipation. The channel characteristics are free from the contact resistance effect due to the large characteristics channel length at a smaller frequency that makes the technique unique. 2-D numerical simulation with Pentacene/Ferro geometry and gold/ITO as top/bottom contact configuration has been simulated to demonstrate the concept and the model. (a) C-V without high k dielectric and without ferro, (b) C-V only with high k dielectric and (c) C-V with high k dielectric and with ferro material. • The channel capacitance of the conventional AMIS structure can be increased significantly by employing a ferroelectric material. • This property can be suitably used for extracting accurate TFT channel properties and also for sensing applications.

Ferroelectricity in hafnium oxide films doped with magnesium by chemical solution deposition

In this study, a series of ∼26 nm thick hafnium oxide films doped with different concentrations of Mg were prepared by the chemical solution deposition method. With the increase of Mg concentration, the film undergoes a phase transition from monoclinic, through orthorhombic, and then to cubic. Metal–insulator–semiconductor capacitors were fabricated, and the ferroelectricity was verified for films doped with an Mg concentration of 0.4–3.7 mol. %. For the film doped with 2.3 mol. % Mg, the remanent polarization is 16.4 μC/cm2 after the wake-up process, and 76.1% of the initial 2Pr value can be maintained after 107 cycles of bipolar field cycling. All the results show that Mg is a promising dopant to stabilize the ferroelectricity of hafnium oxide films.

Capacitance–voltage characteristics of Pt/hBN/WSe2 metal–insulator–semiconductor capacitor doped by charge-transfer process

Metal–insulator–semiconductor (MIS) capacitors composed of low-dimensional van der Waals (vdW) materials are of fundamental interest for understanding carrier transport properties at the atomic scale. Herein, we fabricated a Pt/hBN/WSe2 MIS low-dimensional capacitor, followed by UV/ozone-induced oxidation to form a WOX layer, which is an electron-withdrawing agent. Capacitance–voltage (C–V) characteristics before and after p-doping of the WSe2 layer were compared for different durations of UV/ozone treatments. The C–V behaviors in the pristine condition exhibited ambipolar transport characteristics at both high and low frequencies because of co-existence of electron and hole carriers, which are advantageous for next-generation complementary MIS architectures. When WSe2 was p-doped, a typical p-type C–V curve with a high-frequency inversion region was observed, because the minority carriers (electrons) were unavailable. The frequency dispersions and ratios of the current to pristine hole concentrations as well as holes to electrons at different p-doping concentrations were analyzed. Finally, the controllability of the charge-transfer doping method was confirmed by chemically removing the WOX layer. The understanding of controllable and damage-free doping mechanisms in ambipolar vdW semiconductors is expected to help enhance electronic device performances at the atomic thickness.

Low Interface Trapped Charge Density for AlO/β-GaO (001) Metal-Insulator-Semiconductor Capacitor

In this letter, high-performance Al2O3/β-Ga2O3 (001) metal-insulator-semiconductor (MIS) capacitor has been demonstrated. The capacitance-voltage (C.V) curves of the Al2O3/β-Ga2O3 (001) MIS capacitor remain stable under different measurement frequencies. The leakage current density is lower than 2.0 × 10-8 A/cm2 when the gate voltage is in the range of –5 13 V. The fixed charge and trapped charge densities in Al2O3 film are 4.4 × 1012 and 6.0 × 1011 cm-2, respectively. Average and minimum interface trapped charge density (Dit) for Al2O3/β-Ga2O3 (001) interface has been extracted to be as low as 3.3 × 1011 and 2.3 × 1011 cm-2 eV-1 via the Terman method, respectively. The low Dit is probably attributed to the modification of vacancy defects and the introduction of hydroxyl groups at the Al2O3/β-Ga2O3 (001) interface after piranha solution pretreatment for β-Ga2O3.

Extraction of dipolar coupling constants from low-frequency electrically detected magnetic resonance and near-zero field magnetoresistance spectra via least squares fitting to models developed from the stochastic quantum Liouville equation

We report low-frequency electrically detected magnetic resonance (EDMR) and near-zero field magnetoresistance (NZFMR) measurements observed through spin-dependent trap-assisted tunneling on unpassivated 28Si/28SiO2 metal–insulator–semiconductor (MIS) capacitors. This study both experimentally and theoretically explores the effects of the low-frequency EDMR response and the mechanisms responsible for spin-mixing, which leads to the NZFMR response in the absence of electron–nuclear hyperfine interactions. Previous reports that utilized high-frequency EDMR and NZFMR on these devices indicated that the observed trap-assisted tunneling spectra are dominated by silicon dangling bonds back bonded to silicon at the Si/SiO2 interface, Pb0 and Pb1 centers. These previous results also suggest that the rate limiting step in trap-assisted tunneling is the interface to an oxide trapping event. In this work, we extend the theory to show the explicit connection of the defects observed between the NZFMR response and the EDMR, which has not yet been demonstrated. We also extend a theoretical approach to the analysis of both the EDMR and NZFMR spectra and match the theory to experimental observations made in 28Si/28SiO2 MIS capacitors. The method utilizes a least squares fitting algorithm of models developed from the stochastic quantum Liouville equation. We find that we can extract a dipolar coupling constant by fitting both the NZFMR and EDMR spectra. Our experimental results and resulting fitted spectra from our quantitative model suggest the mechanism responsible for spin-mixing, which leads to the NZFMR response in the absence of electron–nuclear hyperfine interactions, is predominately magnetic dipolar interactions between Pb centers at the interface.

Investigation of the Intrinsic Nature of Organic Semiconductors Using a Metal Contact-Induced Capacitance Study in Organic Metal–Insulator–Semiconductor Capacitors

Investigation of the Intrinsic Nature of Organic Semiconductors Using a Metal Contact-Induced Capacitance Study in Organic Metal–Insulator–Semiconductor Capacitors

Effects of 29Si and 1H on the near-zero field magnetoresistance response of Si/SiO2 interface states: Implications for oxide tunneling currents

We report on a study that offers fundamental physical insight into an important phenomenon in solid state device physics, tunneling in Si/SiO2. We observe near-zero field magnetoresistance via spin-dependent trap-assisted-tunneling in both unpassivated and passivated Si/SiO2 and 28Si/28SiO2 metal–insulator–semiconductor (MIS) capacitors. A previous report, which utilized electrically detected magnetic resonance and NZFMR on these devices, indicates a surprising conclusion: the observed trap-assisted tunneling spectra are dominated by silicon dangling bonds back bonded to silicon at the Si/SiO2 interface, Pb0 and Pb1 centers. In this study, the four sets of samples are virtually identical, apart from the presence or absence of either 1H and 29Si. We observed a substantial narrowing of the NZFMR response with the removal of 29Si nuclei and a substantial broadening with the addition of 1H. Since superhyperfine interactions between 29Si nuclei Pb at the Si/SiO2 interface are a full order of magnitude stronger than such interactions involving silicon dangling bonds defects (E′ centers) within the oxide, the NZFMR results strongly suggest a response dominated by Si/SiO2 interface trap defects. With the introduction of 1H magnetic nuclei to the interface after a forming gas anneal, linewidths and lines shapes of Si/SiO2 and 28Si/28SiO2 MIS capacitors were nearly identical. However, the amplitude of the NZFMR response is greatly reduced by the introduction of hydrogen by a fraction about equal to the reduction in the interface trap density. Our results further indicate that the rate limiting step in trap-assisted tunneling is the interface to oxide trapping event.

(Invited) Fabrication and Characterization of Ge-Based MIS Structures

Germanium (Ge) is a very attractive channel material for future high-performance metal-insulator-semiconductor (MIS) devices because it exhibits much higher low-field electron (two times higher) and hole (four times higher) mobilities than Si. In addition, the smaller band gap of Ge than that of Si should allow the further reduction of power consumption in advanced integrated circuits and the lower melting point of Ge than that of Si also enables Ge-based device integration at low processing temperatures. However, until the early years of the 2000s, the reported electrical properties of high-k/Ge interfaces had been so poor that one of the critical issues in establishing Ge-based MIS technology was the effective passivation of Ge surfaces by dielectrics with superior interface properties. Although the quality of the Ge-MIS structure has been remarkably improved in the past decade, the relationship between the processing methods and the quality has not been discussed precisely.In this paper, we report on the fabrication of Ge MIS structures with various high-k dielectric materials and interlayer materials through various methods. We also introduce the convenient method to characterize the interface trap densities (Dit's) of the MIS capacitors by spectroscopic measurement of the interface trap density in an insulator/Ge interface at room temperature [1]. The effects of the insertion of interlayers into the interface of high-k insulator/Ge and the application of heat treatment to the Ge MIS structures will be also presented.For instance, the Dit of Ta2O5/GeNx/Ge fabricated by electron-cyclotron-resonance (ECR) plasma nitridation and sputtering was estimated to be 4×1011 cm-2 · eV-1 [2], that of Si3N4/GeNx/Ge by ECR plasma nitridation to be 1×1011 cm-2 · eV-1 [3-6], and that of Al2O3/GeO2/Ge by ECR plasma oxidation and sputtering to be 4.5×1010 cm-2 · eV-1 [7-9]. These results have summarized that the adequate surface preparations of the interfaces and films by the ECR plasma process with low energy plasma irradiation have been effective to realize the low Dit of MIS structures with GeO2 and/or GeNx.These results have expanded to another MIS structures fabricated by more conventional film formation technique such as the atomic layer deposition (ALD) and the radio frequency (RF) magnetron sputtering. The Dit of Al2O3/Al germanate/Ge by ALD with trimethylaluminum (TMA) and microwave-generated atomic oxygen was estimated to be 2×1011cm-2 · eV-1 [10], and that of HfO2/Ge by RF magnetron sputtering to be 5.9×1011 cm-2 · eV-1. These results have summarized that the heat treatment after the fabrication of MIS strucures have affected interface properties of germanate/Ge and oxide/Ge.Although the mechanism by which the process conditions act on the interface state is now under estimation, it has been speculated that the fabrication method, the insertion of the interlayers, and the application of heat treatment have a great influence on the interface characteristics. The structures and the fabrication method of various MIS will be discussed.Part of this work was carried out under the Cooperative Research Project Program of the Research Institute of Electrical Communication, Tohoku University.

Electrically detected magnetic resonance and near-zero field magnetoresistance in 28Si/28SiO2

We report on electrically detected magnetic resonance (EDMR) and near-zero-field magnetoresistance (NZFMR) measurements observed through spin-dependent trap-assisted-tunneling on unpassivated Si/SiO2 metal–insulator–semiconductor capacitors comparing those containing silicon of natural isotopic abundance and silicon depleted of 29Si. Although our measurements involve monitoring the spin-dependence of the trap-assisted-tunneling current responsible for leakage across the oxide, the EDMR spectra resemble that of a combination of Pb0 and Pb1 silicon dangling bonds sites at the Si/SiO2 interface. Additionally, we observe a substantial narrowing of the NZFMR response with the removal of 29Si nuclei. The breadth of the NZFMR response is strongly influenced by hyperfine interactions. Since superhyerfine interactions between 29Si nuclei and silicon dangling bonds at the Si/SiO2 interface are a full order of magnitude stronger than such interactions involving silicon dangling bonds defects (E′ centers) within the oxide, the NZFMR results also strongly suggest a response dominated by Si/SiO2 interface trap defects. These results collectively suggest very strongly that the leakage currents that we observe involve tunneling from Si/SiO2 Pb dangling bonds to defects within the oxide. Our results thus offer fundamental insight into technologically important phenomena involving oxide leakage currents in metal–oxide–semiconductor devices such as stress induced leakage currents and time dependent dielectric breakdown.

Demonstration of TiO₂ Based Ultra High-k (k = 30) Metal-Insulator-Semiconductor Capacitor and Its Electrical Properties.

In this paper, we investigated TiO₂ as gate dielectric to achieve the large dielectric constant. The ultra high-k value over 30 was obtained by Capacitance-Voltage measurement of Al/Ti/TiO₂/Si Metal-Insulator-Semiconductor (MIS) capacitor. Among as deposited, rapid thermal annealing (RTA) at 750 °C and 1000 °C, the RTA at 750 °C showed the lowest gate leakage current. It implies that TiO₂ has optimum RTA temperature having the lowest leakage current. When TiO₂ is annealed at 750 °C, the phase of TiO₂ changes to anatase and interfacial layer between TiOx and Si was formed. While TiO₂ is annealed at 1000 °C, the phase of TiO₂ changes to rutile and diffusion of silicon atoms was clearly observed and it causes the silicide formation. Based on measurement data, we proposed the energy band diagram of Al/TiO₂/Si MIS capacitors. This diagram shows that the energy band gap of RTA at 750 °C is expanded while that of RTA at 1000 °C is contracted. In addition, TiO₂ with RTA at 550 °C was tested to confirm leakage current and it shows lower leakage current than RTA at 750 °C as we expected. This result confirmed that optimum RTA temperature of TiO₂ would exist under 750 °C.

Investigation and optimization of HfO2 gate dielectric on N-polar GaN: Impact of surface treatments, deposition, and annealing conditions

UV-assisted capacitance–voltage (C–V) and current–voltage (I–V) measurements were performed on ∼20 nm HfO2/GaN metal–insulator–semiconductor capacitors. The effects of surface preparation, predeposition treatment, HfO2 deposition process, and post-deposition annealing environment on interface characteristics were studied. Surface preparation by etching in diluted BHF and piranha etch prior to atomic layer deposition (ALD) suppressed the interface states compared to the baseline sample possibly due to the removal of the native oxide and impurities. UV/ozone treatment prior to HfO2 deposition reduced the interface states by one order of magnitude compared to the baseline sample possibly due to the formation of a thin Ga2O3 interlayer. In situ ALD pretreatment with tri-methyl-aluminum/N2 plasma was also found to reduce the surface states significantly compared to the baseline sample. In addition, thermal ALD improved the dielectric constant and breakdown voltage of the dielectric as compared to plasma ALD due to less surface damage. The lowest average interface trap density achieved was 1.64 × 1012 cm−2/eV with an HfO2 dielectric constant of 16 on the sample with UV/ozone and piranha treatment with in situ ALD treatment and thermal ALD deposition.

Crystalline AlN Interfacial Layer on GaN Using Plasma-Enhanced Atomic Layer Deposition

In this study, we report on the deposition of a highly crystalline AlN interfacial layer on GaN at 330 °C via plasma-enhanced atomic layer deposition (PEALD). Trimethylaluminum (TMA) and NH3 plasma were used as the Al and N precursors, respectively. The crystallinity and mass density of AlN were examined using X-ray diffraction (XRD) and X-ray reflectivity (XRR) measurements, respectively, and the chemical bonding states and atomic concentrations of the AlN were determined by X-ray photoelectron spectroscopy (XPS). The AlN/n-GaN interface characteristics were analyzed using TOF-SIMS and STEM, and the electrical characteristics of the AlN were evaluated using metal-insulator-semiconductor (MIS) capacitors. The PEALD process exhibited high linearity between the AlN thickness and the number of cycles without any incubation period, as well as a low carbon impurity of less than 1% and high crystal quality even at a low deposition temperature of 330 °C. Moreover, the GaN surface oxidation was successfully suppressed by the AlN interfacial layer. Furthermore, enhanced electrical characteristics were achieved by the MIS capacitor with AlN compared to those achieved without AlN.