Stable Dielectric Properties Research Articles

Molecular design and application of low dielectric bismaleimide resin

AbstractWith the development of communications technology, the copper‐clad laminate (CCL) for integrated circuits (IC) pointed to the direction of high‐frequency and high‐speed development, that is, a lower dielectric constant and dielectric loss requirements. Bismaleimide (BMI) resins feature stable dielectric properties and excellent thermal stability over a wide temperature range, widely used in the manufacture of high‐frequency and high‐speed CCL substrates. However, the comprehensive performance of BMI resin itself, including dielectric properties, still cannot fully meet the needs of the ever‐changing communications industry, so the molecular design modification of BMI resin to enhance the dielectric properties is currently one of the key research directions for integrated circuit CCL. This paper reviews the development of BMI resins and their applications, focusing on the main methods of molecular design modification and formulation optimization, including allyl, diamine, internal chain‐extended, and chemical/physical blending modification. Finally, the low dielectric BMI resin and its application and development in high‐frequency and high‐speed CCL are summarized and prospected. Future research directions include the design and synthesis of multi‐component copolymers to further realize the balance between low dielectric and comprehensive performance, as well as exploring the possibility of novel composite modifications to provide more competitive high‐performance materials for the IC laminate field.Highlights The development of bismaleimide resin and their applications are reviewed. Bismaleimide monomers' synthesis and chemical reaction are summarized. The modified methods of bismaleimide resin in low dielectric are reviewed. Future research directions of low dielectric bismaleimide are prospected.

Harnessing Cu incorporation for achieving stable superior microwave dielectric properties in low permittivity MgSiO3-based ceramics through effective phase transition suppression

MgSiO3 ceramics with a low dielectric constant are highly promising for application in 5G communication due to their excellent performance and cost-effectiveness. However, the application remains constrained by phase transitions. This study aims to unlock their full potential by introducing Cu ions to mitigate phase transitions, thereby achieving stable and superior performance. Mg1-xCuxSiO3 (0 ≤ x ≤ 0.25) ceramics were synthesized by solid-state method, and the effects of Cu introduction on the crystal structure, phase constitution, microstructure and microwave dielectric properties were systematically investigated. Through XRD patterns and Rietveld refinement, it was found that when x = 0, both protoenstatite (PEN) and low-temperature clinoenstatite (CEN) phases coexist due to a phase transition from PEN to CEN. As x increases, the PEN phase dominance rises while the CEN phase diminishes, indicating that the addition of Cu ions inhibits the occurrence of phase transition. At x ≥ 0.2, only the orthoenstatite (OEN) phase was observed. SEM and EDS analyses revealed the beneficial impact of Cu introduction on sintering, yet excessive amounts can lead to abnormal grain growth, local segregation, and uneven distribution of Cu elements, thereby deteriorating microwave dielectric properties. The optimal microwave dielectric performance was achieved at x = 0.05: εr = 6.2, Qf = 93,600 GHz, τf = −33.7 ppm/°C. A one-year long-term comparative study revealed the stabilizing effect of Cu incorporation for obtaining stable excellent performance. These findings underscore the potential of introducing an appropriate amount of Cu to achieve stable and superior microwave dielectric properties in MgSiO3 ceramics, paving the way for practical applications in 5G communication.

Interweaved filler network in epoxy resin with reduced interface thermal resistance via in-situ high-temperature “welding” for significantly improved thermal conductivity

For heterogeneous integration in harsh environments, polymeric materials are required to integrate excellent insulating property with significant thermal conductivity. Traditional discrete fillers used in polymeric matrix to create thermal pathways introduce numerous contact interfaces, leading to limited thermal conductivity enhancement efficiency (TCE) and unstable dielectric properties. Here, a distinctive strategy, involving the preparation of an interweaved thermally conductive filler with inherent heat channels through self-templated electrospinning and in-situ high-temperature “interface welding”, is proposed to reduce the interface thermal resistance (ITR). The growth of grains at high temperature facilitates the process of “interface welding”, while self-templated electrospinning establishes intrinsic thermal conduction pathways. Consequently, the epoxy resin fortified with this interweaved filler exhibits an exceptionally TCE of 162.15 % and enhanced in-plane thermal conductivity of 3.75 W m−1 K−1 at ultra-low filler ratio of 7.10 vol%. The combination of high electrical insulation of filler and low filler content results in excellent electrical insulating property (>1017 Ω cm) and stable dielectric properties over a frequency range of 103-106 Hz, enabling the successful implementation of heterogeneous integration in challenging environments. This work has the potential to offer a groundbreaking approach for achieving interconnected functional networks within polymer-based composites.

Enhanced energy-storage performance with optimized thermally stable dielectric property in BNT–BST ceramics modified by KNN doping

Developing environmental-friendly materials with high-density energy storage is of paramount importance to meet the burgeoning demands for energy storage. In this study, we harness the modulation of a multicomponent solid solution by introducing KNN as a third element into the BNT–BST system, thereby achieving a marked enhancement in both energy storage performance and the temperature stability of the dielectric constant. BNBST–4KNN stands out for its exceptional dielectric stability, with a dielectric constant variation rate within 10% across a broad temperature range of [Formula: see text]C to [Formula: see text]C, a feat attributed to the flattening and broadening of the [Formula: see text] peak. BNBT–2KNN exhibits superior energy storage capabilities, with an energy storage density of 1.324 J/cm3 and an energy storage efficiency of 72.3%, a result of the P–E loop becoming more slender. These advancements are pivotal for the sustainable progression of energy storage technologies.

Transparent ionic liquid antenna based on multi-modes using multiple feeding structures

With the rapid development of modern wireless communication technology, there is an increasing demand for the functionality of the communication system carried by a single platform. To improve the utilization of the antenna, a multimode liquid antenna is proposed in this paper. The antenna is fabricated using 3D printing technology and mainly consists of a cylindrical dielectric resonator, a coaxial feeding structure, and a slot-coupling feeding structure. By hollowing out the middle of a resin container and filling it with low-loss ionic liquid with stable dielectric properties, a liquid dielectric resonator antenna (DRA) is formed. The various resonant modes (slot mode, HEM11δ, TM11δ, TM21δ, and TM31δ modes) can be excited by introducing different feeding structures. The operating frequencies and radiation patterns can be modulated by mode switching. Simulated and measured results show that the antenna operates in the frequency bands of 2.25–2.76 GHz (20.4 %) and 4.82–5.73 GHz (17.3 %), and the maximum gain can be up to 10.3 dBi. The proposed antenna structure avoids the complex RF control circuit design, which has various applications including 5G/6G communications, transparent electronic devices, and Internet of Things.

Dielectric-Loaded Horn Antenna Design and Simulation Using the Metamaterial Method

In this paper, we propose the design and simulation of a dielectric horn antenna using the metamaterial method; this antenna has a double-layer dielectric waveguide transmission structure. With the continuous development of microwave feed sources, the traditional waveguide systems are no longer able to meet today’s antenna requirements. Consequently, dielectric-loading technology is gradually being applied to design horns. A key advantage of this antenna is its significantly expanded bandwidth of 163.3%. Furthermore, when compared to ridge horns, this dielectric-loaded horn demonstrates superior radiation properties across the entire frequency band, including aperture efficiency (95% in the L band, 65.4% in the S band, 41.5% in the C band, and 28.7% in the X band) and cross-polarization isolation (≥51.6 dB). In addition, before researching the theory of dielectric-loading technology, the modes of the horns should be analyzed. This helps us to better control the hybrid mode. The metamaterial method was applied to achieve stable dielectric properties. We finally conducted experiments on the antenna to validate the relevant theories and feasibility.

Stable dielectric properties at high-temperature of Al2O3-PESU composite for energy storage application

Dielectric capacitors, crucial in microelectronics, hybrid vehicles and inverters, are renowned for their rapid charge–discharge capabilities and high energy density. This research introduces a novel strategy to enhance the dielectric properties of polyethersulfone (PESU) matrix materials by incorporating aluminum oxide (Al2O3) powder as a filler. Employing a solution mixing technique, dielectric composite films were synthesized. The 1 wt% Al2O3-PESU composite exhibited exceptional outcomes, presenting a charge–discharge efficiency of 62 % and an impressive energy storage density of 8.4 J/cm3 at 640 kV/mm. Finite element simulations validated enhanced thermal conductivity, reduced electric field distortion, and heightened breakdown strength in the composites. Additionally, cyclic aging demonstrated outstanding stability and reliability over 50,000 cycles. This study propels dielectric material design, charting a course for high-performance energy storage capacitors, accentuating the crucial influence of temperature on dielectric behavior.

Covalently cross-linked CaCu3Ti4O12 and poly(arylene ether nitrile) hybrids with enhanced high temperature energy storage properties

Ensuring polymer dielectrics with stable high energy storage density at high temperatures via improving interfacial compatibility remains a challenge. Based on this principle, calcium copper titanate and poly(arylene ether nitrile) (CCTO-PEN) hybrids dielectrics are developed to exhibit improved high temperature energy storage properties through the interfacial cross-linked high-temperature resistant cyano. Herein, CCTO-PEN hybrid dielectrics are fabricated through the thermal induced self-crosslinking reaction of phthalonitrile between the phthalonitrile modified CCTO (CCTO-CN) and phthalonitrile end-capped PEN (PEN-CN). SEM, XPS, FTIR, mechanical, dielectric, and breakdown tests of the CCTO-PEN hybrids reveal that the phthalonitrile modified CCTO-CN possessed superior interfacial compatibility in PEN dielectrics, together with enhanced dielectric, breakdown, mechanical, and energy storage properties compared to CCTO directly doped PEN dielectrics. Benefitting from the improved interfacial compatibility and the appropriate distribution of CCTO-CN within PEN-CN matrix, the CCTO-PEN hybrids demonstrate stable dielectric properties from room temperature to 200 °C, and the energy storage density of CCTO-PEN hybrid reaches up to 0.785 J/cm3, suggesting that the CCTO-PEN hybrids can be utilized as high temperature dielectric materials.

High performance epoxy composites modified by a ladder-like polysilsesquioxane

Developing transparent epoxy resins (EPs) with high mechanical properties, thermally stable, and superior dielectric properties is of vital importance for electronics and communication application. Here we synthesized a novel ladder-like polysilsesquioxane containing phenyl and amino groups (N-PPSQ) via a facile co-condensation process for EP modification. The N-PPSQ features a highly regular ladder-like structure with several reactive amino groups anchored, as confirmed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and nuclear magnetic resonance silicon spectroscopy (29Si NMR). Different EP/N-PPSQ composites with optimized additive contents were prepared. Compared to the pure EP, 10 wt% N-PPSQ addition helps to increase the impact strength of EP by a maximal 73 % while simultaneously improving the tensile and flexural properties. With maintained high transparency and enhanced hygrothermal stability, the EP/N-PPSQ composite shows lower dielectric constant and dielectric loss than pure EP. The work demos a fine solution to improving the toughness, dielectric properties and hygrothermal stability without sacrificing the mechanical and optical properties of EP.

Defect dipoles and stable dielectric properties improve Nb-doped Ba0.7Sr0.3TiO3 photocatalytic H2 evolution activity

The roles of defect dipoles and the dielectric constant in photocatalytic hydrogen evolution are explored.

Structures, dielectric properties and AC impedance characteristics of BiFeO3–BaTiO3 high-temperature lead-free piezoceramics synthesized by the hydrothermal method

Among the lead-free piezoceramics, ([Formula: see text])BiFeO[Formula: see text]BaTiO3 (BF-BT) is considered a promising candidate for high-temperature piezoelectric materials owing to its high Curie temperature ([Formula: see text]C) and good electromechanical properties. In this work, the hydrothermal synthesis method was used to prepare the precursor powders of BiFeO3 and BaTiO3, and then the mixed powder compacts with the chemical composition of 0.7BF–0.3BT were sintered under pressureless conditions. The influence of the hydrothermal reaction times (12–24[Formula: see text]h) of BiFeO3 on the structures and electric properties of the sintered ceramics was instigated. First, all the samples synthesized with the tetragonal BaTiO3 and BiFeO3 powders were identified with relatively stable dielectric properties. As the hydrothermal reaction time to synthesize BiFeO3 increased, the dielectric properties as well as the temperature stability of the 0.7BiFeO3–0.3BaTiO3 ceramics also improved. At the condition of a hydrothermal reaction time of 24[Formula: see text]h, the sample obtained possesses both the lowest temperature coefficient of dielectric constant ([Formula: see text]C between RT and [Formula: see text]C) and the highest Curie temperature ([Formula: see text]C at 100[Formula: see text]kHz). Moreover, at high temperatures, it exhibits a higher AC impedance than others. The calculating result based on the resistive constant-phase-element model (R-CPE) circuit model showed that the grain boundary of the 0.7BF–0.3BT ceramics contributes more resistance to the conductivity at high temperatures. In summary, the hydrothermal reaction proved to be a useful way that achieves the preparation of single-phase 0.7BF–0.3BT ceramics with improved electrical properties.

Substantial improvement of thermal conductivity and mechanical properties of polymer composites by incorporation of boron nitride nanosheets and modulation of thermal curing reaction

AbstractThermal conductive polymer‐based composites synchronously with stable dielectric and excellent mechanical properties are urgently needed for high‐temperature‐resistant electronic devices. Here, a significant improvement in the thermal conductivity (TC), thermal stability, dielectric, and mechanical performance was simultaneously achieved in the polyarylene ether nitrile (PEN)/divinyl siloxane‐bisbenzocyclobutene (BCB) matrix through the incorporation of boron nitride nanosheets (BNNS) combined together with the post‐solid phase chemical reaction technique. The significant increase in the effective filler‐filler and filler‐crystal contacts in the composites was the main reason for the improvement in TC and dielectric constant. Besides, glass transition temperature (Tg) and mechanicals were enhanced in the presence of cross‐linked networks. By synchronously adding 15 vol% BNNS, the TC of composites after treatment reached up to 5.582 W/m.K, enhanced by 4.4 times higher than untreated. The dielectric constant was down to 2.93 at 1 MHz and the loss remained at a relatively low level. Meanwhile, the composite showed significantly enhanced thermal stability, mechanicals, and hydrophobicity (Tg = 336°C, T5% = 529°C, tensile strength and modulus was 94.5 MPa and 5.3 GPa, respectively, the contact angle was 101.76°). Thus, it promotes an effective strategy for fabricating a high‐performance‐polymer composite, which has the potential used in electronic materials.Highlights Crystallization‐crosslinking strategy optimizes overall performance. Crystals fill gaps between BNNS layers and connect thermal conductive pathway. Crosslinked networks limit molecular chain motion to reduce phonon scattering. The highest TC of the PEN/BCB/BNNS composite is up to 7.451 W/m.K. Thermal property shows significant improvement after crosslinking especially Tg.

3D printing of a SiO2@BN TPMS structure: Efficient heat transfer strategy for BN/epoxy composites

The high integration density of microelectronic devices leads to local heat accumulation, and effective heat dissipation and signal transmission of packaging materials have become the primary issues to be solved. However, existing polymer materials have difficulty meeting the requirements due to their unsatisfactory thermal conductivity and thermal expansion properties. In this work, we proposed the use of digital light processing (DLP) printing technology to construct a triply periodic minimum surface (TPMS) skeleton, and a continuous and efficient heat conduction path was successfully constructed in epoxy resin by impregnating h-BN on the skeleton surface. When the loading of h-BN was 20 vol%, the thermal conductivity of the TPMS(SiO2)@BN/EP(BN) composites was 1.86 W/(m·K), which was 786 % higher than that of pure epoxy resin. In addition, the thermal expansion coefficient of the composites decreased by more than 70 %. At the test frequencies of 3∼10 MHz, the composites showed stable dielectric properties, and the dielectric constant was always maintained in a low range, between 3.85 and 4.15. This work has realized the transformation of the method for constructing a heat conduction path from disordered to ordered and from random to repeatable. This provides a new strategy for the selection of microelectronic packaging materials.

Ca-Sn co-substituted BiIn-YIG ferrite with narrow FMR linewidth for microwave device application

The requirements for improving the performance and miniaturizing microwave devices have led to higher demands for the yttrium iron garnet (YIG) ferrite materials. To achieve YIG ferrite materials with narrow ferromagnetic resonance (FMR) linewidths, and stable magnetic and dielectric properties, Ca-Sn co-substituted YIG samples with the composition Bi0.4Y2.6-xCaxFe4.65-xIn0.35SnxO12 were synthesized via solid-state sintering at 1230 °C. The microstructural, magnetic, and dielectric properties of the samples were systematically tested and analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), impedance analyzer, vibrating sample magnetometry (VSM), and ferromagnetic resonance (FMR). The results indicate that the co-substitution of Ca2+ and Sn4+ ions did not alter the crystal structure of YIG ferrites, and effectively improved the microstructure and performance of the material. When the doping concentration (x) was 0.40, the obtained sample exhibited the narrowest FMR linewidth (ΔH = 43.46 Oe) and excellent magnetic and dielectric properties (4πMs = 1555.68 G, ε′ = 14.12 @ 100 MHz). The material proposed in this study demonstrates significant potential for applications in microwave devices.

Preparation of graphitic carbon nitride (g-C3N4) for novel dielectric and photocatalytic dye removal applications

Recent developments in 2D nanomaterials have greatly expanded their use in engineering applications. Graphitic carbon nitride (g-C3N4) shows a combination of electrical conductivity, sensing and luminescence abilities, biocompatibility, and chemical stability. The present study showcases the effectiveness of g-C3N4 as a photocatalyst for removing various organic molecules from water (such as methylene blue, 4-nitrophenol, and pharmaceutical drugs) and its potential use in dielectric applications when combined with an organic polymer (polyvinylidene fluoride; PVDF). XRD patterns confirmed the formation of g-C3N4 (which is complimented by the UV-Visible and FTIR results) and PVDF-g-C3N4 composite film. SEM-EDS verified the chemical homogeneity of the as-prepared g-C3N4 powder. Maximum photocatalytic degradation was observed for methylene blue dye (96.48%) with a half-life of 24.18 min, whereas the least degradation was detected for hydroxychloroquine (53.10%) with a half-life of 90.12 min after 120 min of UV-visible exposure. 10 wt% C3N4 reinforced PVDF thick films exhibited stable dielectric properties at low temperature (below 60°C) as compared to PVDF alone. At 1 kHz, the dielectric permittivity and tangent loss of the PVDF-g-C3N4 composites come out to be ∼6 and ∼0.05, respectively (at room temperature). The AC conductivity and activation energy of the synthesized composite was also studied.

Perspective on dielectric properties of calcium copper titanate ceramics

Calcium Copper Titanium Oxide (CCTO) Ceramics of composition CaCu3Ti4O12 has emerged as a lead-free ceramic supercapacitor with a large dielectric constant of 104–105 at room temperature. The CCTO microstructure is electrically heterogeneous composed of semiconducting grains and insulating grain boundaries. The origin of the large dielectric constant has therefore been widely attributed to barrier layer capacitance originated at grain boundaries. Our research is focused on understanding the stability and reproducibility of the measured electrical and dielectric properties when they are used as capacitor dielectrics because of the inconsistent results obtained when tested in ambient conditions. The origin of this inconsistency is investigated through the roles of testing atmosphere, sample thickness and doping with alumina on the stability and reproducibility of dielectric properties of CCTO. The solid state reaction method is used to fabricate phase pure and dense samples. AC impedance spectroscopy is used to study the roles of testing atmospheres, temperatures, microstructures, grain boundaries, sample thickness, alumina doping and frequency on the dielectric properties. It is shown that this approach of characterizing fundamental electrical properties of CCTO can be used to eliminate hysteresis to produce stable and reproducible dielectric properties. These perspectives are presented and discussed.

Emerging nonoxide dielectrics for next‐generation electronics

AbstractAs electronic devices continue to develop, there is a growing demand for materials capable of supporting new physical properties, such as flexibility, stretchability, low‐temperature processability, applicability to large areas or ultra‐thin films, and operation at extremely low voltages. Metal oxide dielectrics, such as silicon dioxide, aluminum oxide, and hafnium oxide, offer excellent dielectric properties, but their ability to meet these new properties and the choice of substrate is limited. Therefore, a new dielectric material capable of providing stable dielectric properties with new functionalities is required. In this review, we briefly introduce the physical principles of dielectric materials and the recent trends of nonoxide dielectrics which satisfy requirements of new functionalities. We discussed various nonoxide dielectric materials of organic, self‐assembled mono/multilayers, electrolytes, two‐dimensional (2D) materials, and metal halides. Finally, we conclude with an outlook and challenges on dielectric materials for next‐generation micro‐ and macro‐electronics.

Development of high-temperature stable dielectric material

Temperature stability is one of the important parameters for the capacitor to work in various temperature ranges. BaTiO3-based materials are one of the popular choices as X7R, X8R, X9R, and X8T (class II) materials in capacitors due to the high value and temperature stability of their dielectric permittivity. Several studies have revealed that the property and performance of these materials can be tailored by doping different elements at A and B sites. In this work, Ba(1-x) Srx Zr 0.1Ti0.9O3 + 2 wt% MgO (x = 0,0.02,0.04) was synthesized via the solid-state reaction method. Liquid phase sintering was adopted to assist in the formation of dense microstructures. For this purpose, MgO was used as a sintering aid. We studied the structural, morphological, dielectric, and energy storage properties of these composites. The powder X-ray diffraction pattern confirmed the formation of cubic phase in Ba(1-x) Srx Zr0.1Ti0.9O3. FESEM micrograph of these compositions revealed that the sample had been properly sintered and possesses a dense microstructure. In dielectric measurement, the εr -T and tanδ -T curves have been plotted for different compositions at different frequencies. The result showed stable dielectric properties with the variation of temperature in all composites, which is characteristic of temperature-stable dielectric materials. For all the compositions, it has been found that there is a decrease in dielectric constant with the frequency, which is due to a decrease in polarisations of the atoms or molecules with the increase in frequency. The flatness of the dielectric curve confirms that the studied material is highly preferable for Class II dielectric-type capacitors. The broadening of the dielectric peak is observed for all the compositions because of the diffusive phase transition. The variation of capacitance or ∊r in terms of TCC is –33 to +22% for a wide range of temperatures from −55 °C to +150 °C.

Temperature-Invariant Large Broadband Polyimide Dielectrics with Multimodal Porous Networks

Herein, we describe sponge-like polymeric materials with multimodal porous networks with stable ultralow dielectric properties over broad frequency and temperature ranges. A hierarchically porous polyimide (PI) film was prepared via nonsolvent-induced phase separation (NIPS), followed by stepwise thermal imidization. Through the swelling and the subsequent liquid–liquid phase separation, highly insulating interconnected pores of the internal layer and the water-vapor impermeable, closed-cell skin of the outer layer were directly formed on the PI film. The grafting of porous PI onto amino-functionalized mesoporous silica (AMS) to further adjust the overall thermal stability and dielectric constant has become a valid strategy. The porous PI-grafted-AMS (PPI-g-AMS) exhibited uniform micropores, which were regularly shaped with an average diameter of 16.3 ± 0.6 μm. The glass transition temperature (Tg) of PPI-g-AMS increased considerably from 367 °C to as high as 398 °C because of the formation of interchain cross-linking bridges in the AMS. Outstanding dielectric constant (Dk) and dissipation factor (Df) of 1.84 and 0.0018 at a frequency of 1 MHz, respectively, were achieved for PPI-g-AMS-1 with the addition of AMS with 1% wt. Moreover, stable and ultralow Dk (∼1.84 at 1 MHz) and Df (∼0.001 at 1 MHz) values were achieved over a broad temperature range from −20 to 200 °C. These findings indicate the broad application potential of polymeric materials as interlevel insulation materials in the next-generation 5G/6G infrastructure.

Effect of ferroelectric phase evolution on dielectric and piezoelectric properties in yttrium-doped BNT-BT ceramics

Lead-free Yttrium-substituted 0.94(Bi0.5-xYxNa0.5TiO3)-0.06(BaTiO3) (BYNT-6BT) ceramics with x = 0, 0.01, 0.02, 0.03 and 0.05 were prepared by conventional solid-state reaction route. The effects of Y3+ substitution into A-site on the crystal structure, microstructure, dielectric, ferroelectric and field induced strain (S-E) behavior of BNT-6BT were examined. X-ray diffraction data revealed that Y2O3 in the amount of 0.1–0.5 wt% can substitute the lattice of BNT-6BT ceramics forming a pure perovskite phase without any secondary peaks. Y3+ introduction enhanced the ferroelectric properties (remnant polarization (Pr) = 36.5 μC/cm2, coercive field (Ec) = 32.96 kV/cm) at x = 0.01 and piezoelectric properties (converse/dynamic piezoelectric constant (d*33) = 327 pm/V at applied electric field of 5 kV/mm) at x = 0.02, which can be attributed to phase evolution and high relative density. Y3+ substitution reduced the relative permittivity, while temperature stability of BNT-6BT was expanded as the Y3+ content increased, which is credited to phase evolution from normal ferroelectric to relaxor ferroelectrics. Outstanding stability range of dielectric permittivity (εr) ±15% from 97 to 500 °C having low dielectric loss (tan δ < 0.01) was achieved at an optimum composition (x = 0.05). The thermally stable dielectric properties of the current study imply that BYNT-BT could be a potential choice for high temperature dielectric applications.