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Article

Marina Santo Zarnik, Darko Belavic and Srecko Macek

The successful use of piezoceramic thick films in sensors and actuators requires a thorough understanding of their electrical and electromechanical characteristics. Since…

Abstract

Purpose

The successful use of piezoceramic thick films in sensors and actuators requires a thorough understanding of their electrical and electromechanical characteristics. Since these characteristics depend not only on the material's composition but also on its compatibility with various substrates and a number of processing parameters, accurate measurements of the material's parameters are essential. Here, the aim of this paper is to present a procedure for characterising lead‐zirconate‐titanate (PZT) thick films on pre‐fired low‐temperature co‐fired ceramic (LTCC) substrates performed in order to determine the material parameters for numerical modelling.

Design/methodology/approach

Owing to the lack of standard procedures for measuring the elastic and piezoelectric properties of the films, the compliance parameters were evaluated from the results of nano‐indentation tests, and a substrate‐flexure method was used to evaluate the transverse piezoelectric coefficients.

Findings

The validation of the material model and the finite‐element (FE) analysis of the demonstrator sensor/actuator structures are shown to be in agreement with the FE model, even if not an exact fit.

Originality/value

This paper focuses on a characterisation of PZT thick films screen‐printed on pre‐fired LTCC substrates.

Details

Microelectronics International, vol. 25 no. 2
Type: Research Article
ISSN: 1356-5362

Keywords

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Article

Marina Santo Zarnik, Darko Belavič and Srečko Maček

The purpose of this paper is to consider a capacitive pressure sensor fabricated using low‐temperature cofired ceramic (LTCC) materials and technology as a candidate for…

Abstract

Purpose

The purpose of this paper is to consider a capacitive pressure sensor fabricated using low‐temperature cofired ceramic (LTCC) materials and technology as a candidate for an energy‐autonomous sensor application. Designing the 3D capacitive sensor structure, with the cofired thick‐film electrodes inside the narrow air gap in the LTCC substrate, was a challenging task, particularly due to the presence of the parasitic elements influencing the sensor's characteristics.

Design/methodology/approach

In this work, different design variants for the thick‐film electrodes of the capacitive sensing structure were studied and compared. The test sensors were designed for the pressure range 0‐10 kPa and manufactured with readout electronics based on a capacitance‐to‐digital conversion.

Findings

The typical sensitivity obtained was 4 fF/kPa, and the temperature coefficient of the sensitivity was 0.03%/°C. The design variant with the guard‐ring electrode showed the best rms resolution of 50 Pa. One drawback of the application could be the sensitivity to atmospheric humidity and the influence of the different media.

Originality/value

This paper focuses on the design of a capacitive gas‐pressure sensor in a 3D LTCC structure. The present study provides a good basis for further optimisation of the design of the cofired electrodes in the capacitive sensing structure.

Details

Microelectronics International, vol. 28 no. 3
Type: Research Article
ISSN: 1356-5362

Keywords

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Article

Darko Belavic, Marko Hrovat, Marina Santo Zarnik, Andreja Bencan, Walter Smetana, Roland Reicher and Heinz Homolka

Strain gauges can be realised by printing and firing thick‐film resistors on ceramic substrates that are usually based on alumina. However, sensing elements made on some…

Abstract

Strain gauges can be realised by printing and firing thick‐film resistors on ceramic substrates that are usually based on alumina. However, sensing elements made on some other substrates – tetragonal zirconia or stainless steel – would exhibit some improved characteristics, either due to a lower modulus of elasticity or a higher mechanical strength. As thick‐film resistors are developed for firing on alumina substrates their compatibility and possible interactions with other kinds of substrates have to be evaluated. The sheet resistivities and noise indices of the resistors were comparable, whereas the gauge factors were lower for the dielectric‐on‐steel substrates. The temperature coefficients of resistivity (TCR) of the resistors on the ZrO2 and dielectric‐on‐steel substrates were higher than the TCRs on the alumina substrates, which was attributed to the higher thermal expansion coefficient of the tetragonal zirconia and the stainless steel.

Details

Microelectronics International, vol. 20 no. 2
Type: Research Article
ISSN: 1356-5362

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Article

Marko Pavlin, Darko Belavic, Marina Santo Zarnik, Marko Hrovat and Matej Mozek

Pressure‐sensor miniaturization requires high‐density packaging. This means that designers are constantly faced with all kinds of challenging, and sometimes impossible…

Abstract

Pressure‐sensor miniaturization requires high‐density packaging. This means that designers are constantly faced with all kinds of challenging, and sometimes impossible, requirements. In this paper we will present three examples with specific technologies and aspects of miniaturization and packaging. The first example is a pressure switch, the second a pressure sensor and the third a smart pressure sensor.

Details

Microelectronics International, vol. 19 no. 3
Type: Research Article
ISSN: 1356-5362

Keywords

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