Tejinder Singh

Effective Stress Modeling of Membranes Made of Gold and Aluminum Materials Used in Radio-Frequency Microelectromechanical System Switches

Microelectromechanical system switches are becoming more and more popular in the electronics industry; there is a need for careful selection of the materials in the design and fabrication of switches for reliability and performance issues. The membrane used for actuation to change the state of an RF switch is made mostly using gold or aluminum. Various designs of membranes have been proposed. Due to the flexure-type structures, the design complexity increases, which makes stress analysis mandatory to validate the reliability and performance of a switch. In this paper, the effective stress and actuation voltage required for different types of fixed-fixed membranes is analyzed using finite element modeling. Effective measures are presented to reduce the stress and voltage.

Status of UV Imprint Lithography for Nanoscale Manufacturing

For over a decade, imprint lithography literature has touted the remarkable sub-10 nm resolution and the promise of low-cost, large-area nanoscale manufacturing. However, there has been legitimate skepticism from the device community about the viability of imprint lithography in manufacturing because of a lack of comprehensive development in areas such as long-range order, overlay, low defectivity, mask life, and high throughput. In recent years, it has become evident that imprint lithography is maturing in its manufacturing attributes not only due to development in basic technology and the infrastructure around it but also due to application drivers, specifically high-density data storage including patterned magnetic media and solid-state memory. These early applications are likely to lead to additional high-impact applications of imprint lithography in several other sectors. Here, a status of ultraviolet (UV) imprint lithography technology is provided with a specific focus on its applicability to high-volume manufacturing of nanoscale devices.

Stress Analysis Using Finite Element Modeling of a Novel RF Microelectromechanical System Shunt Switch Designed on Quartz Substrate for Low-voltage Applications

This paper presents a novel shunt radio frequency microelectromechanical system switch on a quartz substrate with stiff ribs around the membrane. The buckling effects in the switch membrane and stiction problem are the primary concerns with RF MEMS switches. These effects can be reduced by the proposed design approach due to the stiffness of the ribs around the membrane. A lower mass of the beam and a reduction in the squeeze film damping is achieved due to the slots and holes in the membrane, which further aid in attaining high switching speeds. The proposed switch is optimized to operate in the k-band, which results in a high isolation of -40 dB and low insertion loss of -0.047 dB at 21 GHz, with a low actuation voltage of only 14.6 V needed for the operation the switch. The membrane does not bend with this membrane design approach. Finite element modeling is used to analyze the stress and pull-in voltage.

High Isolation Single-Pole Four-Throw RF MEMS Switch Based on Series-Shunt Configuration

This paper presents a novel design of single-pole four-throw (SP4T) RF-MEMS switch employing both capacitive and ohmic switches. It is designed on high-resistivity silicon substrate and has a compact area of 1.06 mm2. The series or ohmic switches have been designed to provide low insertion loss with good ohmic contact. The pull-in voltage for ohmic switches is calculated to be 7.19 V. Shunt or capacitive switches have been used in each port to improve the isolation for higher frequencies. The proposed SP4T switch provides excellent RF performances with isolation better than 70.64 dB and insertion loss less than 0.72 dB for X-band between the input port and each output port.

From Theory to Development: Role of Multiphysics Modeling and its Effect on Education in Electronics

Electronics engineering is a very rapidly growingfield, as the time passes the requirement of more advance technologiesincrease. There are a lot of institutions and universitiesaround the world that provide quality education to different fieldsof engineering. The courses that electronics engineers study needpractical exposure as well to cope up with industrial demands. Inthis paper, the role of multiphysics modeling and its impact onengineering education is demonstrated. Finite element modeling(FEM) tools are very powerful tools and due to there hugeadvantages, electronics graduates should study these tools in theircourse curriculum to know how to tackle various types of physicsproblems and through examples it is demonstrated that how thesetools can help shift from just theory to development process.

Harsh Environment Materials

In this chapter semiconductor microsystems materials and devices are discussed, which are outside the reach of traditional Si-based MEMS technologies. The semiconductors discussed here are wide bandgap semiconductors with ceramic-like stability, namely SiC, GaN and GaN-based heterostructures, AIN, and diamond. At first, the general materials technologies and properties are introduced, including the polarization effects of wurzite GaN and AIN. The environments considered are high mechanical stresses, high temperature, high energy radiation and particle detection, and highly aggressive gases, and highly corrosive liquid media. This is followed by a discussion of the transducer elements realized up to now in these materials, both sensors and actuators. The ceramic-like materials properties and the extraordinary applications require in many cases microsystems technologies, which differ essentially from those of Si-MEMS technologies. This is discussed next. Since the materials technologies of wide bandgap semiconductors used for extreme applications are still rather immature, most devices are still discrete and hybrid integrated into systems. Such integration approaches are reviewed shortly. Finally selected examples are given, which have been realized based on thin film diamond.

Biocompatibility of Microsystems

In the coming years micro devices will become an increasingly important part of medical technology and revolutionize many areas in clinical therapy and diagnostics. Microengineered devices will create new diagnostic tools, allow a therapeutic intervention at a very local level, and improve the long-term monitoring of patients. Through the development of such microsystem tools, medical diagnosis, and therapy will completely change. In addition new devices will help to diminish the occurrence of critical situations which could cause severe harm to the patient. Microengineering will allow the generation of new implantable devices which allow one to recover bodily functions lost through illness or injury.

A Novel Stiff Membrane Seesaw Type RF Microelectromechanical System DC Contact Switch on Quartz Substrate

This paper proposes a novel RF MEMS dc-contact switch with stiff membrane on a quartz substrate. The uniqueness of this work lies in the utilization of a seesaw mechanism to restore the movable part to its rest position. The switching action is done by using separate pull-down and pull-up electrodes, and hence operation of the switch does not rely on the elastic recovery force of the membrane. One of the main problems faced by electrostatically actuated MEMS switches is the high operational voltages, which results from bending of the membrane, due to internal stress gradient. This is resolved by using a stiff and thick membrane. This membrane consists of flexible meanders, for easy movement between the two states. The device operates with an actuation voltage of 6.43 V, an insertion loss of -0.047 dB and isolation of -51.82 dB at 2 GHz.

A novel capacitive RF MEMS switch design for low voltage applications

This paper presents a novel capacitive radio frequency Microelectromechanical systems switch on quartz substrate having stiff ribs around the membrane. Due to the need of high voltage for electrostatic actuation; buckling effect in switch membrane and stiction problem become the primary concern with RF MEMS switches and can be reduced with this proposed design approach due to the stiffness of ribs around the membrane. Lower mass of the beam and reduction in squeeze film damping is achieved due to the slots and holes in membrane that further aid in attaining high switching speeds. Two actuation electrodes are provided to increase the actuation area thus helps n achieving lower actuation voltages. This proposed switch is optimized to operate in k-band that results in high isolation of -41 dB and low insertion loss of -0.034 dB at 21 GHz with need of low actuation voltage of 9.7 V for operation of the switch.

Materials for Microsystems

As the design of microsystems (MST) or microelectromechanical systems (MEMS) matures and migrates from process centric to performance based design, MEMS designers would need a rational method for selecting an appropriate material that is not based on the ease of processing alone. While there is a growing number of thin film materials that can be used for MEMS devices, the selection of a particular material is rarely based on quantifiable criterion that relates directly to the optimum performance of the device. This article describes issues on materials selection for MEMS from a designer?s point of view.