Metal-insulator-metal Devices Research Articles

Weld-free mounting of lamellae for electrical biasing operando TEM

Recent advances in microelectromechanical systems (MEMS)-based substrates and sample holders for in situ transmission electron microscopy (TEM) are currently enabling exciting new opportunities for the nanoscale investigation of materials and devices. The ability to perform electrical testing while simultaneously capturing the wide spectrum of signals detectable in a TEM, including structural, chemical, and even electronic contrast, represents a significant milestone in the realm of nanoelectronics. In situ studies hold particular promise for the development of Metal-Insulator-Metal (MIM) devices for use in next-generation computing. However, achieving successful device operation in the TEM typically necessitates meticulous sample preparation involving focused ion beam (FIB) systems. Conducting contamination introduced during the FIB thinning process and subsequent attachment of the sample onto a MEMS-based chip remains a formidable challenge. This article delineates an improved FIB-based sample preparation methodology that results in good electrical connectivity and operational functionality across various MIM devices. To exemplify the efficacy of the sample preparation technique, we demonstrate preparation of a clean cross section extracted from a Au/Pt/BaSrTiO3/SrMoO3 tunable capacitor (varactor). The FIB-prepared TEM lamella mounted on a MEMS-based chip showed current levels in the tens of picoamperes range at 0.1 V. Furthermore, the electric response and current density of the TEM lamella device closely align with macro-scale devices. These samples exhibit comparable current densities to their macro-sized counterparts thus validating the sample preparation process and confirming device connectivity. The simultaneous operation and TEM characterization of electronic devices enabled by this process enables direct correlation between device structure and function, which could prove pivotal in the development of new MIM systems.

The planar anodic Al2O3-ZrO2 nanocomposite capacitor dielectrics for advanced passive device integration

ABSTRACT The need for integrated passive devices (IPDs) emerges from the increasing consumer demand for electronic product miniaturization. Metal-insulator-metal (MIM) capacitors are vital components of IPD systems. Developing new materials and technologies is essential for advancing capacitor characteristics and co-integrating with other electronic passives. Here we present an innovative electrochemical technology joined with the sputter-deposition of Al and Zr layers to synthesize novel planar nanocomposite metal-oxide dielectrics consisting of ZrO2 nanorods self-embedded into the nanoporous Al2O3 matrix such that its pores are entirely filled with zirconium oxide. The technology is utilized in MIM capacitors characterized by modern surface and interface analysis techniques and electrical measurements. In the 95–480 nm thickness range, the best-achieved MIM device characteristics are the one-layer capacitance density of 112 nF·cm−2, the loss tangent of 4·10−3 at frequencies up to 1 MHz, the leakage current density of 40 pA·cm−2, the breakdown field strength of up to 10 MV·cm−1, the energy density of 100 J·cm−3, the quadratic voltage coefficient of capacitance of 4 ppm·V−2, and the temperature coefficient of capacitance of 480 ppm·K−1 at 293–423 K at 1 MHz. The outstanding performance, stability, and tunable capacitors’ characteristics allow for their application in low-pass filters, coupling/decoupling/bypass circuits, RC oscillators, energy-storage devices, ultrafast charge/discharge units, or high-precision analog-to-digital converters. The capacitor technology based on the non-porous planar anodic-oxide dielectrics complements the electrochemical conception of IPDs that combined, until now, the anodized aluminum interconnection, microresistors, and microinductors, all co-related in one system for use in portable electronic devices.

Impact of the temperature on the conductive filament morphology in HfO2-based RRAM

In this letter, we study the impact of the temperature on the resistive switching effect of TiN/Ti/HfO2/W metal–insulator-metal devices. An analysis of the conduction mechanisms is made, with the low resistance state being ruled by nearest neighbor hopping, while the conduction in the high resistance state is dominated by Schottky emission. Taking into account the filamentary mechanism behind the resistive switching effect, a thorough analysis of the Schottky emission allows for the calculation of the gap between conductive filament tip and metal electrode in the high resistance state. We report an increase of this gap when temperature lowers below a certain value. Moreover, the mentioned gap adopts values of integer multiples of the the mean distance between traps obtained by the hopping model.

Inkjet‐Printed Flexible Thin‐Film Thermal Sensors for Detecting Elevated Temperature Range

All inkjet‐printed thermal sensors are manufactured based on a metal–insulator–metal (MIM) interface or capacitor architecture, for the adapted device size ranging from 16 to 36 mm2 active area. Two different material inks, namely a nanoparticle conductive silver ink and an inorganic‐polymer‐based hybrid insulator ink, are applied layer by layer on a thin flexible polyimide substrate, for developing the printed MIM devices. To ensure the desired electronic conductivity and insulation from the layers, the manufacturing process steps and parameters are tuned, accordingly. The results show that the inkjet‐printed MIM devices could constitute up to 15 μm thickness and demonstrate average detection of a change in electrical capacitance ranging from 20 to 100 pF, when the temperature is varied between 100 and 300 °C. The investigations also summarize that the change in the electrical response is enough to detect an increment of 50 °C. The printed sensors also display high operational stability and repeatability, when subjected to thermal cycling.

HfOx/Ge RRAM with High ON/OFF Ratio and Good Endurance

A trade-off between the memory window and the endurance exists for transition-metal-oxide RRAM. In this work, we demonstrated that HfOx/Ge-based metal-insulator-semiconductor RRAM devices possess both a larger memory window and longer endurance compared with metal-insulator-metal (MIM) RRAM devices. Under DC cycling, HfOx/Ge devices exhibit a 100× larger memory window compared to HfOx MIM devices, and a DC sweep of up to 20,000 cycles was achieved with the devices. The devices also realize low static power down to 1 nW as FPGA’s pull-up/pull-down resistors. Thus, HfOx/Ge devices act as a promising candidates for various applications such as FPGA or compute-in-memory, in which both a high ON/OFF ratio and decent endurance are required.

Bifunctional MIM device with narrowband filtering and high-performance sensing

We propose a fundamental plasmonic system consisting of a metal-insulator-metal (MIM) waveguide and a semi-ring resonator. This system can achieve Fano resonances to realize high-performance sensing and narrowband filtering. A pair of horizontal cavities are placed above and below the waveguide, respectively. When light propagates along the waveguide, resonances are excited in the upper and lower cavities simultaneously, and then couple with each other in the semi-ring. Changing the relative position of the upper and lower cavities can produce Fano resonances. We use finite-difference time-domain (FDTD) for the simulation and coupled-mode theory(CMT) theory to demonstrate the principles of the structure. The structure has very high sensitivity of 1025 nm/RIU and FOM value of 36.1 dB.

Interfacial engineering of ZrO2 metal-insulator-metal capacitor using Al2O3/TiO2 buffer layer for improved leakage properties

ABSTRACT The continuous scale-down of dynamic random-access memory (DRAM) requires shrinkage of high aspect ratio metal-insulator-metal (MIM) capacitance along with the successful suppression of its leakage current to maintain desired levels of charge storage and retention. As the dimensions of stacked insulating dielectric and metal electrodes in the MIM capacitor are currently <10 nm, interfacial mixing has a large impact on the reliability of the capacitor. This is because defects and secondary interface oxides significantly alter the physicochemical properties of MIM capacitors. The methodology required to characterize ultrathin interfaces in relation to the performance of MIM devices is highly challenging due to its physical and chemical complexities of interface between dielectric and electrode. In this study, a ZrO2-based dielectric film and its interface (with an ultrathin TiO2/Al2O3 buffer layer) are analyzed using angle-resolved X-ray photoelectron spectroscopy (ARXPS), spectroscopic ellipsometry (SE), and temperature dependent I–V analysis for a DRAM MIM capacitor. The composite dielectric layer included either Al2O3 on the bottom or Al2O3/TiO2 between the TiN electrode and ZrO2. This study suggests an effective metrology approach to characterize ultrathin MIM capacitors and the important role of interfacial stabilization using a buffer layer for the effective control of leakage current.

Application of Solution Method to Prepare High Performance Multicomponent Oxide Thin Films.

Capacitors play an increasingly important role in hybrid integrated circuits, while the MIM capacitors with high capacitance density and small thickness can meet the needs of high integration. Generally speaking, the films prepared with a single metal oxide dielectric often achieve a breakthrough in one aspect of performance, but dielectric layers are required to be improved to get better performance in leakage current, capacitance density, and transmittance simultaneously in modern electronic devices. Therefore, we optimized the performance of the dielectric layers by using multiple metal oxides. We combined zirconia, yttria, magnesium oxide, alumina, and hafnium oxide with the solution method to find the best combination of these five metal oxides. The physical properties of the multi-component films were measured by atomic force microscopy (AFM), ultraviolet-visible spectrophotometer, and other instruments. The results show that the films prepared by multi-component metal oxides have good transmittance and low roughness. The thicknesses of all films in our experiment are less than 100 nm. Then, metal–insulator–metal (MIM) devices were fabricated. In addition, we characterized the electrical properties of MIM devices. We find that multi-component oxide films can achieve good performances in several aspects. The aluminum-magnesium-yttrium-zirconium-oxide (AMYZOx) group of 0.6 M has the lowest leakage current density, which is 5.03 × 10−8 A/cm2 @ 1.0 MV/cm. The hafnium-magnesium-yttrium-zirconium-oxide (HMYZOx) group of 0.8 M has a maximum capacitance density of 208 nF/cm2. The films with a small thickness and a high capacitance density are very conducive to high integration. Therefore, we believe that multi-component films have potential in the process of dielectric layers and great application prospects in highly integrated electronic devices.

Electroluminescence of NV by impact excitation and Stark shift in a MIM diamond structure

Electrically driven emission of nitrogen-vacancy (NV) color centers in diamond has recently emerged as a viable candidate for quantum photonics. However, it is challenging to efficiently excite NV centers by an electric field because of the low density of free carriers in doped diamond. Here, we report efficient electroluminescence of neutrally charged nitrogen-vacancy (NV0) color centers under a high electric field (105 V/cm) and study its Stark effect in a MIM (Metal–Insulator–Metal) diamond device. The MIM device was fabricated by electron beam evaporating molybdenum electrodes and microwave plasma chemical vapor depositing a nitrogen-doped diamond epilayer successively on a single-crystal diamond substrate. We demonstrate the field dependence of the electrically driven emission and extract the NV0 ground state electric field susceptibility of 15.83 ± 0.86 GHzmMV−1 from the Stark effect at 5.5 K. Our findings provide a perspective toward electrically exciting color centers in diamond and help one to understand the inherent features of NV0.

Optical-Field-Driven Electron Tunneling in Metal-Insulator-Metal Nanojunction.

Optical‐field driven electron tunneling in nanojunctions has made demonstrable progress toward the development of ultrafast charge transport devices at subfemtosecond time scales, and have evidenced great potential as a springboard technology for the next generation of on‐chip “lightwave electronics.” Here, the empirical findings on photocurrent the high nonlinearity in metal–insulator–metal (MIM) nanojunctions driven by ultrafast optical pulses in the strong optical‐field regime are reported. In the present MIM device, a 14th power‐law scaling is identified, never achieved before in any known solid‐state device. This work lays important technological foundations for the development of a new generation of ultracompact and ultrafast electronics devices that operate with suboptical‐cycle response times.

Light‐Assisted Resistive Switching Memory Device with Reduced SET/RESET Voltage Using Sol–Gel TiO2 on Al‐Doped ZnO Electrode

Herein, light‐assisted resistive switching (RS) characteristic of low‐cost sol–gel TiO2 film‐based metal–insulator–metal (MIM) configuration using Al‐doped ZnO (AZO) as the bottom electrode is demonstrated. Unprecedentedly, instead of the costly transparent conducting electrode such as tin‐doped indium oxide, AZO electrode is exploited in this study due to its dual role as a transparent and an additional oxygen vacancy (VO)‐rich electrode. The Al/TiO2/AZO device shows electroforming free bipolar RS characteristics, which can be explained by the formation (rupture) of conducting filaments composed of VO. The memory window is increased three times under the blue light illumination compared to dark conditions. Interestingly, the SET and RESET voltages are decreased from 5.2 to 4.5 V and −3.9 to −3.3 V, respectively, under the blue light illumination with respect to the dark condition. The enhancement in the RS effect under the blue light illumination is explained in terms of the photoresponsive properties of TiO2. The MIM device exhibits good switching repeatability with stable retention characteristics, making them attractive for next‐generation nonvolatile resistive random access memory devices.

Optical-Cavity-Induced Current

The formation of a submicron optical cavity on one side of a metal–insulator–metal (MIM) tunneling device induces a measurable electrical current between the two metal layers with no applied voltage. Reducing the cavity thickness increases the measured current. Eight types of tests were carried out to determine whether the output could be due to experimental artifacts. All gave negative results, supporting the conclusion that the observed electrical output is genuinely produced by the device. We interpret the results as being due to the suppression of vacuum optical modes by the optical cavity on one side of the MIM device, which upsets a balance in the injection of electrons excited by zero-point fluctuations. This interpretation is in accord with observed changes in the electrical output as other device parameters are varied. A feature of the MIM devices is their femtosecond-fast transport and scattering times for hot charge carriers. The fast capture in these devices is consistent with a model in which an energy ∆E may be accessed from zero-point fluctuations for a time ∆t, following a ∆E∆t uncertainty-principle-like relation governing the process.

Effect of Zirconium Doping on Electrical Properties of Aluminum Oxide Dielectric Layer by Spin Coating Method with Low Temperature Preparation

In recent years, significant efforts have been devoted to the research and development of spin-coated Al2O3 thin films, due to their large band gaps, high breakdown voltage and stability at high annealing temperature. However, as the alumina precursor has a large surface energy, substrates need to be treated by plasma before spin coating. Therefore, to avoid the expensive and process-complicated plasma treatment, we incorporated zirconium nitrate into the aluminum nitrate solution to decrease the surface energy of the precursor which improve the spreadability. Then, the electrical performances and the surface morphologies of the films were measured. For comparison, the pure Al2O3 films with plasma treatments were also prepared. As a result, after low temperature annealing (200 °C), the relative dielectric constant of Zr–AlOx spin-coated thin-film MIM (Metal-Insulator-Metal) devices can reach 12 and the leakage current density is not higher than 7.78 × 10−8 A/cm2 @ 1 MV/cm when the concentration of zirconium nitrate is 0.05 mol/L. The Aluminum oxide film prepared by zirconium doping has higher stability and better electrical properties than the pure films with plasma treatments and high performance can be attained under low-temperature annealing, which shows its potential application in printing and flexible electronic devices.

Characterization of aluminum oxide thin films obtained by chemical solution deposition and annealing for metal–insulator–metal dielectric capacitor applications

A novel chemical formulation is presented that enables the chemical solution deposition of aluminum hydroxide thin films, which transforms into aluminum oxide through subsequent annealing. The proposed method represents a faster and more economical alternative for aluminum oxide thin film deposition that can be used in metal-insulator-metal (MIM) dielectric capacitor applications. The film properties were studied in detail via X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and optical spectroscopy. It is demonstrated that the obtained thin films present high optical quality, low-crystalline domains, and oxygen vacancies. The films that were obtained for a 30 min deposition time show a suitable surface morphology and thickness, determined by atomic force microscopy and a cross-section from scanning electron microscopy, of a dielectric layer which was used to fabricate a MIM device. Using capacitance-voltage and current-voltage characterizations on that device, a low leakage current in the 10−4 A/cm2 range and a capacitance of 98 and 48 nF/cm2 were measured. These results indicate that, both aluminum hydroxide and aluminum oxide thin films have dielectric properties that are comparable to those of silicon oxide. Thus, the proposed method allows the deposition of gate dielectric films at low temperatures through a technically simple and scalable process.

Enhanced resistive switching in graphene oxide based composite thin film for nonvolatile memory applications

The uniform and stable bipolar switching characteristics of Graphene Oxide (GO) based metal insulator metal (MIM) structure embedded with titanium dioxide (TiO2) nanoparticles (NPs) on ITO/glass substrate has been investigated. In this paper the effect of TiO2 concentration on switching characteristics of Al/GO-TiO2/ITO MIM devices were studied. Thin film of composite (GO-TiO2) was deposited on conductive indium tin oxide (ITO) glass using spin coating technique. The incorporation of TiO2 NPs in GO thin film increased the number of oxygen vacancies which were responsible for formation and rupture of conducting filament between two electrodes of Aluminum and ITO. It was observed that Al/GO-TiO2 (4 mg)/ITO require low voltage to switch from OFF state (High Resistance State) to ON state (Low Resistance State) and vice versa as compared to Al/GO/ITO device. Switching behavior of the fabricated devices were investigated using current voltage characteristics. The dispersion of TiO2 (4 mg) NPs in GO reduced the switching voltage by almost 50% than the bare graphene oxide thin film. The retention behavior of fabricated device was tested upto 4*103 s and endurance behavior upto 60 cycles which didn’t exhibit any degradation. Carrier transport mechanism in the devices has been explained on the basis of current voltage characteristics in HRS and LRS. These composite based resistive random access memory devices have great potential as a future nonvolatile low power memory.

(Invited) Optimized HfO2-Based MIM Module Fabrication for Emerging Memory Applications

The demand for the high-density integrated memories is growing along with the scaling of the transistor technology nodes. To fabricate the reliable devices in advanced technologies, optimization of several process steps is necessary [1]. The capacitor, which is commonly a MIM (Metal-Insulator-Metal) module finds its application as a basic storage device in memories, filters, voltage limiters etc. The MIM module is also considered as an integral part of memory technologies such as DRAM, FeRAM, and RRAM. The MIM modules should demonstrate reliable operation through better performance and efficiency. And, it is realized through the parameters related to MIM module such as, low leakage current, less variability with respect to capacitance, high quality factor Q, lower defect density, low parasitic capacitance and many others [2]. Reactive-ion-etching plays a very important role in BEOL integration of MIM devices. The MIM module is created by dry etching through the MIM stack. Related to RRAM (Resistive Random Access Memory) applications the MIM stack consists of an additional buffer layer such as Ti or Hf [3]. These layers are easily oxidizable and the etching step could oxidize them from the sidewalls. Also, the residuals of the metal if remain on the sidewall could lead to leaky devices. Hence, an etch process which is not well optimized could damage the devices and in turn pose a threat to their functionality and reliability [4]. An improved MIM stack etch process is beneficial to reduce the above-mentioned damages. Several techniques were used in the past to cover the MIM devices with dielectric materials like SiO2 and SiN, which protects the devices from further process steps involved in the fabrication procedure [5]. In this work we demonstrate the effect of the improved etch process with a combination of SiNO spacers and encapsulation techniques for TiN/Ti/HfO2/TiN stacks. This stack is most popularly used in RRAM and, in this work, it is integrated into the BEOL of the 250 nm CMOS technology at IHP. To test the performance of the devices, the MIM stack was fabricated in three different approaches. In the first approach, photoresist is used as a mask to etch the MIM stack, the second one uses TiN hard mask and the third one uses TiN hard mask etch in addition to creation of SiNO spacers after the TiN/Ti etch. The encapsulation of MIM modules with SiNO is implemented in all the three approaches mentioned above. Special device structures with the TiN/Ti/HfO2/TiN stack are fabricated to test the variability of the MIM parameters on the entire wafer. Additionally, the switching operation was tested by means of DC voltage sweeps on the MIM RRAM devices which includes, forming, reset and set steps followed by 50 cycles of reset and set processes. The devices associated with the improved fabrication process steps exhibited less variability in terms of leakage current, capacitance and Q-factor values along the entire wafer. This reduction in the variability of the parameters corresponding to the MIM devices could be used for emerging applications. References G.S. Kar, A.Fantini, Y.Y. Chen, V. Paraschiv, B. Govorenau, H. Hody, N. Jossart, H.Tielens, S. Brus, O. Richard, T. Vandeweyer, D.J. Wouters, L. Altimime, M. Jurczak, i n Symposium on VLSI Technology (VLSIT), 2012 IEEE, pp. 157-158E. Pérez, A. Grossi, C. Zambelli, M. K. Mahadevaiah, P. Olivo, and Ch. Wenger, in MTT-S International Microwave Workshop Series on Advanced Materials and Processes for RF and THz Applications (IMWS-AMP), 2018 IEEE, pp. 1-3E. Pérez, M. K. Mahadevaiah, C. Zambelli, P. Olivo, and Ch. Wenger, Solid-State Electronics, (2019) V. B. Naik, J. H. Lim, K. Yamane, D. Zeng, H. Yang, N. Thiyagarajah, J. Kwon, N. L. Chung, R. Chao, T. Ling, K. Lee, in International Reliability Physics Symposium (IRPS), 2019 IEEE, pp. 2C-2Y.S. Chen, H.Y. Lee, P.S. Chen, P.Y. Gu, W.H. Liu, W.S. Chen, Y.Y. Hsu, C.H. Tsai, F. Chen, M.J. Tsai, and C. Lien, Electron Device Letters, Vol. 32, Issue: 3, pp 390-392 (2011)

Plasmonic metamaterial using metal-insulator-metal nanogratings for high-sensitive refraction index sensor

We propose two designs of plasmonic metamaterial mid-infrared (MIR) sensors, which are composed of metallic nanograting on SiO2 layer with a bottom mirror to form metal–insulator-metal (MIM) configurations. These MIM configurations are denoted as MIM-S and MIM-D to represent MIM composed of single metal nanograting and double metal nanogratings, respectively. The electromagnetic responses of MIM-S and MIM-D are investigated and compared with and without embedded a SiO2 layer between top nanograting and bottom mirror layer. By changing the height of insulator layer, the absorption spectra of MIM-S can be tuned with a linearly wavelength tuning range of 2.4 μm. Furthermore, MIM-D exhibits not only tunable resonance by changing the gap between top and bottom nanogratings, but also switch characteristics by changing the horizontal shift of top nanograting. For the environment sensor application, MIM-S and MIM-D exhibit the sensitive/insensitive to refraction index and tunable FSR characteristics by changing ambient refraction index. Such results provide the MIM devices can be used as multifunctional sensors. This study proposes an implementation strategy of actively tunable filter, switch, and high-sensitive refraction index sensor in the MIR wavelength range.

Harvesting Electromagnetic Energy in the &lt;inline-formula&gt; &lt;tex-math notation="LaTeX"&gt;${V}$ &lt;/tex-math&gt; &lt;/inline-formula&gt;-Band Using a Rectenna Formed by a Bow Tie Integrated With a 6-nm-Thick Au/HfO2/Pt Metal–Insulator–Metal Diode

In this paper, the first demonstration of a bow-tie antenna integrated with a metal–insulator–metal (MIM) diode for electromagnetic energy harvesting in the ${V}$ -band (i.e., 40–75 GHz) is presented. We have designed, simulated, fabricated, and fully characterized a 60-GHz rectifying antenna (rectenna) based on a vertical Au-HfO2-Pt MIM diode with reduced differential resistance. The dielectric used for the MIM structure is a 6-nm-thick amorphous HfO2 grown by atomic layer deposition. For the fabricated MIM device, we report here a current density of ${3} \times {10}^{ {4}}$ A/cm2 that exceeds the previous values presented in the literature. The vertical MIM-based rectenna is able to efficiently harvest up to $250~\mu \text{V}$ from an impinging modulated millimeter-wave signal with −20 dBm of available power, thus offering a voltage responsivity of over 5 V/W. The reported results indicate that the proposed approach is well suited for future low-power solutions much sought after for the energetically autonomous 5G terminal equipment.

Impedance modeling of silica nanoparticle metal insulator metal capacitors

In this study, we have fabricated metal-insulator-metal (MIM) capacitors where the insulator layer is made of 255 nm diameter silica nanospheres. The MIM devices have been characterized and modeled by electrochemical impedance spectroscopy (EIS) and charge-discharge transients. Fitting the results with modified Randles models agreed well with three constant phase elements, three leakage resistors, and a Warburg element. According to the results of the fitting of the charge-discharge measurements and of the modified Randles model, values of real capacitances up to thousand times larger than the theoretical capacitance of a similar capacitor with a continuous layer dielectric are found. These unexpected high capacitances seemed to be related to the ability of the nanospheres to trap electric charges due to surface hydroxyl groups that are originated by the adsorption of water molecules, thereby indicating that the environmental humidity plays a role. This has been ascertained by measurements at several temperatures above the ambient and the resulting capacitance decreases as temperatures increases. Furthermore, active and reactive parts of the complex power have been measured showing capacitive or resistive behavior depending on the frequency. These results suggest that this novel MIM device based on nanospheres may be a new baseline technology for supercapacitor technology.

Characterization of the Failure Site Distribution in MIM Devices Using Zoomed Wavelet Analysis

The angular wavelet analysis is applied to the study of the spatial distribution of breakdown (BD) spots in Pt/HfO2/Pt capacitors with square and circular areas. The method is originally developed for rectangular areas, so a zoomed approach needs to be considered when the observation window does not coincide with the device area. The BD spots appear as a consequence of the application of electrical stress to the device. The stress generates defects within the dielectric film, a process that ends with the formation of a percolation path between the electrodes and the melting of the top metal layer because of the high release of energy. The BD spots have lateral sizes ranging from 1 μm to 3 μm and they appear as a point pattern that can be studied using spatial statistics methods. In this paper, we report the application of the angular wavelet method as a complementary tool for the analysis of the distribution of failure sites in large-area metal–insulator–metal (MIM) devices. The differences between considering a continuous or a discrete wavelet and the role played by the number of BD spots are also investigated.