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Article
Publication date: 20 January 2012

Mahanth Prasad, R.P. Yadav, V. Sahula and V.K. Khanna

The purpose of this paper is to help reduce power consumption by using platinum‐based microhotplate with different dielectric membranes SiO2 and Si3N4 for gas sensing…

Abstract

Purpose

The purpose of this paper is to help reduce power consumption by using platinum‐based microhotplate with different dielectric membranes SiO2 and Si3N4 for gas sensing applications, and to develop platinum lift‐off process using DC sputtering method for fabrication of platinum resistor.

Design/methodology/approach

Semiconductor gas sensors normally require high power consumption because of their elevated operating temperature 300‐600°C. Considering the thermal resistant and sensitive characteristics of metal platinum as well as heat and electricity insulating characteristics of SiO2, Si3N4 and combination of both, a kind of the Si‐substrate microhotplate was designed and simulated using ANSYS 10.0 tool. Thermal oxidation of Si wafer was carried out to get a 1.0 μm thick SiO2 layer. Pt deposition on oxidized silicon substrate by lift‐off was carried out using DC sputtering technique.

Findings

The platinum‐based microhotplate requires 31.3‐70.5 mW power to create the temperature 348‐752°C for gas sensing applications. The SiO2 membrane can operate the gas sensitive film at higher temperature than the Si3N4 and combination of both the membranes at same power consumption. The paper also presents the FEM simulation of different heating elements like nichrome and tantalum and its comparison to platinum for microhotplate applications.

Originality/value

Both the simulation and experimental work provides the low cost, high yield and repeatability in realization of microhotplate. The design and simulation work provides the better selection of heating elements and dielectric membranes. The developed experimental process provides the easy fabrication of platinum resistors using DC sputtering technique.

Details

Sensor Review, vol. 32 no. 1
Type: Research Article
ISSN: 0260-2288

Keywords

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Article
Publication date: 18 January 2016

Robert Bogue

This paper aims to illustrate how sensors can be fabricated by combining nanomaterials with micro-electromechanical system (MEMS) technology and to give examples of…

Abstract

Purpose

This paper aims to illustrate how sensors can be fabricated by combining nanomaterials with micro-electromechanical system (MEMS) technology and to give examples of recently developed devices arising from this approach.

Design/methodology/approach

Following a short introduction, this paper first identifies the benefits of MEMS technology. It then discusses the techniques for integrating carbon nanotubes with MEMS and provides examples of physical and molecular sensors produced by these methods. Combining other gas-responsive nanomaterials with MEMS is then considered and finally techniques for producing graphene on silicon devices are discussed. Brief concluding comments are drawn.

Findings

This shows that many physical and molecular sensors have been developed by combining nanomaterials with MEMS technology. These have been fabricated by a diverse range of techniques which are often complex and multi-stage, but significant progress has been made and some are compatible with standard CMOS processes, yielding fully integrated nanosensors.

Originality/value

This provides an insight into how two key technologies are being combined to yield families of advanced sensors.

Details

Sensor Review, vol. 36 no. 1
Type: Research Article
ISSN: 0260-2288

Keywords

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Article
Publication date: 19 January 2015

Fatemeh Samaeifar, Hassan Hajghassem, Ahmad Afifi and Hassan Abdollahi

One of the key components of the micro-sensors is MEMS micro-hotplate. The purpose of this paper is to introduce a platinum micro-hotplate with the proper geometry using…

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Abstract

Purpose

One of the key components of the micro-sensors is MEMS micro-hotplate. The purpose of this paper is to introduce a platinum micro-hotplate with the proper geometry using the analytical model based on the heat transfer analysis to improve both heating efficiency and time constant.

Design/methodology/approach

This analytical model exhibits that suitable design for the micro-hotplate can be obtained by the appropriate selection of square heater (LH) and tether width (WTe). Based on this model and requirements of routine sample loading, the size of LH and WTe are chosen 200 and 15 μm, respectively. In addition, a simple micro-fabrication process is adopted to form the suspended micro-heater using bulk micromachining technology.

Findings

The experimental results show that the heating efficiency and heating and cooling time constants are 21.27 K/mW and 2.5 ms and 2.1 ms, respectively, for the temperature variation from 300 to 400 K in the fabricated micro-hotplates which are in closed agreement with the results obtained from the analytical model with errors within 5 per cent.

Originality/value

Our design based on the analytical model achieves a combination of fast time constant and high heating efficiency that are comparable or superior to the previously published platinum micro-hotplate.

Details

Sensor Review, vol. 35 no. 1
Type: Research Article
ISSN: 0260-2288

Keywords

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Article
Publication date: 25 June 2019

D.K. Kharbanda, N. Suri and P.K. Khanna

The purpose of this paper is to explore a new possibility of providing high-temperature stable lead-free interconnections for low-temperature co-fired ceramics (LTCC…

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91

Abstract

Purpose

The purpose of this paper is to explore a new possibility of providing high-temperature stable lead-free interconnections for low-temperature co-fired ceramics (LTCC) hotplate. For gas-sensing application, a temperature range of 200°C-400°C is usually required by the sensing film to detect different gases which imply the requirement of thermally stable interconnects. To observe the effect of parameters influencing power of the device, electro-thermal simulation of LTCC hotplate is also presented. Simulated LTCC hotplate is fabricated using the LTCC technology.

Design/methodology/approach

The proposed task is to fabricate LTCC hotplate with interconnects through vertical access. Dedicated via-holes generated on the LTCC hotplate are used to provide the interconnections. These interconnections are based on adherence and bonding mechanism between LTCC and thick film. COMSOL software is used for finite element method (FEM) simulation of the LTCC hotplate structure.

Findings

Thermal reliability of these interconnections is tested by continuous operation of hotplate at 350°C for 175 h and cycling durability test performed at 500°C. Additionally, vibration test is also carried out for the hotplate with no damage observed in the interconnections. An optimized firing profile to reproduce these interconnections along with the experimental flowchart is presented.

Research limitations/implications

Research activity includes design and fabrication of LTCC hotplate with metal to thick-film based interconnections through vertical access. Research work on interconnections based on adherence of LTCC and thick film is limited.

Practical implications

A new way of providing lead-free and reliable interconnections will be useful for gas sensor fabricated on LTCC substrate. The FEM results are useful for optimizing the design for developing low-power LTCC hotplate.

Originality/value

Adherence and bonding mechanism between LTCC and thick film can be used to provide interconnections for LTCC devices. Methodology for providing such interconnections is discussed.

Details

Soldering & Surface Mount Technology, vol. 32 no. 1
Type: Research Article
ISSN: 0954-0911

Keywords

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Article
Publication date: 18 April 2008

Vinod Kumar Khanna

To provide an insight of the intricacies of ion‐sensitive field‐effect transistor (ISFET) encapsulation and describe the presently available packaging solutions…

Abstract

Purpose

To provide an insight of the intricacies of ion‐sensitive field‐effect transistor (ISFET) encapsulation and describe the presently available packaging solutions, indicating how the packaging requirements can be complied for various applications.

Design/methodology/approach

ISFET packaging is a complete subject in itself. The paper includes examples of the different packaging strategies that have been offered by literature and company findings over the past few decades.

Findings

ISFET packaging has progressed from the initial epoxy embedding of the wire bonds and contact pads to the more sophisticated techniques capable of automation wherein moulds are made for epoxy coating or the chip is tightened between contacting parts using elastomer gaskets.

Research limitations/implications

The emerging packaging technologies have succeeded in making chip packaging more a science than an art, and the new methods are capable of large‐scale manufacturing with greater precision.

Practical implications

Packaging solutions for demanding applications of ISFETs have been provided by the upcoming technologies.

Originality/value

The information provided in this paper is of immense value to researchers working on ISFET encapsulation.

Details

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

Keywords

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Article
Publication date: 23 December 2019

Lokesh Kulhari, Achu Chandran, Kanad Ray and P.K. Khanna

Low temperature co-fired ceramics (LTCC) technology-based micro-hotplates are of immense interest owing to their ruggedness, high temperature stability and reliability…

Abstract

Purpose

Low temperature co-fired ceramics (LTCC) technology-based micro-hotplates are of immense interest owing to their ruggedness, high temperature stability and reliability. The purpose of this paper is to study the role of thermal mass of LTCC-based micro-hotplates on the power consumption and temperature for gas-sensing applications.

Design/methodology/approach

The LTCC micro-hotplates with different thicknesses are designed and fabricated. The role of thermal mass on power consumption and temperature of these hotplates are simulated and experimentally studied. Also, a comparison study on the performance of LTCC and alumina-based hotplates of equivalent thickness is done. A thick film-sensing layer of tin oxide is coated on LTCC micro-hotplate and demonstrated for the sensing of commercial liquefied petroleum gas.

Findings

It is found from both simulation and experimental studies that the power consumption of LTCC hotplates was decreasing with the decrease in thermal mass to attain the same temperature. Also, the LTCC hotplates are less power-consuming than alumina-based one, owing to their superior thermal characteristics (low thermal conductivity, 3.3 W/ [m-K]).

Originality/value

This study will be beneficial for designing hotplates based on LTCC technology with low power consumption and better stability for gas-sensing applications.

Details

Microelectronics International, vol. 37 no. 1
Type: Research Article
ISSN: 1356-5362

Keywords

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