Electrical properties and electrical equivalent models of thick‐film and LTCC microcapacitors

Miś, Edward; Dziedzic, Andrzej; Nitsch, K.

doi:10.1108/13565360910960240

Cited by 6 publications

(5 citation statements)

References 5 publications

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“…The later element, G, represents the acoustic interaction between transistor gates caused by piezoelectric coupling [19][20][21]. The exact values of these parameters are adjusted to fit the simulation curve to measurements (the characteristic slope is a result of the effect of the capacitance value and the transmittance value on the amplitude of the oscillations).…”

Section: Resultsmentioning

confidence: 99%

Study of Acoustic Emission from the Gate of Gallium Nitride High Electron Mobility Transistors

Paszkiewicz,

Dziedzic

2024

Electronics

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Nitrides are the leading semiconductor material used for the fabrication of high electron mobility transistors (HEMTs). They exhibit piezoelectric properties, which, coupled with their high mechanical stiffness, expand their versatile applications into the fabrication of piezoelectric devices. Today, due to advances in device technology that result in a reduction in the size of individual transistor elements and due to increased structural complexity (e.g., multi-gate transistors), the integration of piezoelectric materials into HEMTs leads to an interesting occurrence, namely acoustic emission from the transistor gate due to piezoelectric effects. This could affect the device’s performance, reliability, and durability. However, this phenomenon has not yet been comprehensively described. This paper aims to examine this overlooked aspect of AlGaN/GaN HEMT operation, that is, the acoustic emission from the gate region of the device induced by piezoelectric effects. For this purpose, dedicated test structures were designed, consisting of two narrow 1.7 μm-wide metallization strips placed at distances ranging from 5 μm to 200 μm fabricated in AlGaN/GaN heterostructures to simulate and examine the gate behavior of the HEMT transistor. For comparison, the test device structures were also fabricated on sapphire, which is not a piezoelectric material. Measurements of acoustic and electrical interactions in the microwave range were carried out using the “on wafer” method with Picoprobe’s signal–ground–signal (SGS)-type microwave probes. The dependence of reflectance |S11| and transmittance |S21| vs. frequency was investigated, and the coupling capacitance was determined. An equivalent circuit model of the test structure was developed, and finite element method simulation was performed to study the distribution of the acoustic wave in the nitride layers and substrate for different frequencies using Comsol Multiphysics software. At frequencies up to 2–3 GHz, the formation of volume waves and a surface wave, capable of propagating over long distances (in the order of tens of micrometers) was observed. At higher frequencies, the resulting distribution of displacements as a result of numerous reflections and interferences was more complicated. However, there was always the possibility of a surface wave occurrence, even at large distances from the excitation source. At small gate distances, electrical interactions dominate. Above 100 µm, electrical interactions are comparable to acoustic ones. With further increases in distance, weakly attenuated surface waves will dominate.

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Section: Resultsmentioning

confidence: 99%

Study of Acoustic Emission from the Gate of Gallium Nitride High Electron Mobility Transistors

Paszkiewicz,

Dziedzic

2024

Electronics

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“…For a parallel plate capacitive device with high capacitance, at low frequencies, the interconnector (wires) impedance is much lower compared with that of the dielectric material. In case of devices with a thin dielectric, such as capacitors based on thick film and a thin layer of cofired-ceramic dielectric, the contact impedance can be comparable to that of dielectric [9,10]. However, since the dielectric materials studied in this work are relatively thick and demonstrate reasonably high impedance in the temperature and frequency ranges, therefore, only the dielectric impedance is considered for these capacitive devices; and the circuit is electrically modeled approximately as a parallel circuit composed of an ideal capacitor (without parasitic self-inductance and conductance) for polarization current and an ideal parallel resistor (without parasitic capacitance and selfinductance) for conduction and dielectric loss current.…”

Section: Methodsmentioning

confidence: 98%

“…The AUTO mode of the impedance meter was used to select/verify that the RC parallel circuit model was suitable to the dielectric. The AC impedance of a capacitive device is usually composed of impedances of interconnectors (wires), metal/dielectric interfacial contact, and the dielectric material in series [9]. For a parallel plate capacitive device with high capacitance, at low frequencies, the interconnector (wires) impedance is much lower compared with that of the dielectric material.…”

Section: Methodsmentioning

confidence: 99%

Electrical Performance of Cofired Alumina Substrates at High Temperatures

Chen¹

2013

Journal of Microelectronics and Electronic Packaging

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AbstractÀA 96% polycrystalline alumina (Al 2 O 3 ) based prototype packaging system with Au thick-film metallization successfully facilitated long term testing of high temperature SiC electronic devices for over 10,000 h at 5008C previously. However, the 96% Al 2 O 3 chip-level packages of this prototype system were not fabricated via a commercial cofire process, which would be more suitable for large scale commercial production. The cofired alumina materials adopted by the packaging industry today usually contain several percent of glass constituents to allow cofiring processes at temperatures usually lower than the regular sintering temperature for alumina. In order to answer the question of whether cofired alumina substrates can provide a reasonable high temperature electrical performance comparable to regular 96% alumina sintered at 17008C, this paper reports on the dielectric performance of a selected high temperature cofired ceramic (HTCC) alumina substrate and a low temperature cofired ceramic (LTCC) alumina (polycrystalline aluminum oxides with glass constituents) substrate from room temperature to 5508C at frequencies of 120 Hz, 1 KHz, 10 KHz, 100 KHz, and 1 MHz. Parallel-plate capacitive devices with dielectrics of these cofired alumina and precious metal electrodes were used for measurement of the dielectric properties of the cofired alumina materials in the temperature and frequency ranges. The capacitance and AC parallel conductance of these capacitive devices were directly measured by an AC impedance meter, and the dielectric constant and parallel AC conductivity of the dielectric were calculated from the capacitance and conductance measurement results. The temperature and frequency dependent dielectric constant, AC conductivity, and dissipation factor of selected LTCC and HTCC cofired alumina substrates are presented and compared with those of 96% alumina. Metallization schemes for cofired alumina for high temperature applications are discussed to address the packaging needs for low-power 5008C SiC electronics.

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“…The AUTO mode of the impedance meter was used to select/verify that the RC parallel circuit model was suitable to the dielectric. The AC impedance of a capacitive device is usually composed of impedances of interconnectors (wires), metal/dielectric interfacial contact, and the dielectric material in series [6]. For a parallel plate capacitive device with high capacitance, at low frequencies, the interconnector (wires) impedance is much lower compared with that of the dielectric material.…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Dielectric Performance of a High Purity HTCC Alumina at High Temperatures - A Comparison Study with other Polycrystalline Alumina

Chen

2014

Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT)

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A very high purity (99.99+%) high temperature co-fired ceramic (HTCC) alumina has recently become commercially available. The raw material of this HTCC alumina is very different from conventional HTCC alumina, and more importantly there is no glass additive in this alumina material for co-firing processing. Previously, selected HTCC and LTCC (low temperature co-fired ceramic) alumina materials were evaluated at high temperatures as dielectric and compared to a regularly sintered 96% polycrystalline alumina (96% Al2O3), where 96% alumina was used as the benchmark. A prototype packaging system based on regular 96% alumina with Au thick-film metallization successfully facilitated long term testing of high temperature silicon carbide (SiC) electronic devices for over 10,000 hours at 500°C. In order to evaluate this new high purity HTCC alumina for possible high temperature packaging applications, the dielectric properties of this HTCC alumina substrate were measured and compared with those of 96% alumina and a previously tested LTCC alumina from room temperature to 550°C at frequencies of 120 Hz, 1 KHz, 10 KHz, 100 KHz, and 1 MHz. A parallel-plate capacitive device with dielectric of the HTCC alumina and precious metal electrodes were used for measurements of the dielectric constant and dielectric loss of the co-fired alumina material in the temperature and frequency ranges. The capacitance and AC parallel conductance of the capacitive device were directly measured by an AC impedance meter, and the dielectric constant and parallel AC conductivity of the dielectric were calculated from the capacitance and conductance measurement results. The temperature and frequency dependent dielectric constant, AC conductivity, and dissipation factor of the HTCC alumina substrate are presented and compared to those of 96% alumina and a selected LTCC alumina. Other technical advantages of this new co-fired material for possible high packaging applications are also discussed.

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Electrical properties and electrical equivalent models of thick‐film and LTCC microcapacitors

Cited by 6 publications

References 5 publications

Study of Acoustic Emission from the Gate of Gallium Nitride High Electron Mobility Transistors

Study of Acoustic Emission from the Gate of Gallium Nitride High Electron Mobility Transistors

Electrical Performance of Cofired Alumina Substrates at High Temperatures

Dielectric Performance of a High Purity HTCC Alumina at High Temperatures - A Comparison Study with other Polycrystalline Alumina

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