MEMS BASED CZT RADIATION DETECTORS

BY: PRASHANT KUMAR EEE-F6

15715604911

Contents• Introduction• Components of MEMS(Micro Electro-

Mechanical Systems)• Materials for MEMS manufacturing• MEMS basic processes• Technologies for MEMS fabrication• MEMS applications • CZT detectors• CZT detectors applications

Introduction

MEMS is a technology that in its most general form can be defined as miniaturized mechanical and electro-mechanical elements (i.e., devices and structures) that are made using the techniques of micro-fabrication.

The critical physical dimensions of MEMS devices can vary from one micron to several millimeters.

The types of MEMS devices can vary from relatively simple structures having no moving elements, to extremely complex electromechanical systems with multiple moving elements under the control of integrated microelectronics

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COMPONENTS OF MEMS The functional elements of MEMS are

miniaturized structures, sensors, actuators, and microelectronics.

Micro-sensors and micro-actuators are appropriately categorized as “transducers”, which are defined as devices that convert energy from one form to another.

Microelectronic integrated circuits can be thought of as the "brains" of a system.

Microstructures means these miniaturized sensors, actuators, and structures can all be merged onto a common silicon substrate along with integrated circuits .

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MATERIALS FOR MEMS MANUFACTURING

SILICON

POLYMERS

METALS

CERAMICS

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MEMS BASIC PROCESSES

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DEPOSITION PROCESSES PHYSICAL DEPOSITION CHEMICAL DEPOSITION

PATTERNING

LITHOGRAPHY PHOTOLITHOGRAPHY ELECTRON BEAM LITHOGRAPHY ION BEAM LITHOGRAPHY X-RAY LITHOGRAPHY

ETCHING PROCESSES WET ETCHING DRY ETCHING

DIE PREPARATION

FABRICATING MEMS

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BULK MICROMACHINING:

SURFACE MICROMACHINING:

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DEEP REACTIVE ION ETCHING OF SILICON:

DEEP REACTIVE ION ETCHING OF GLASS :

LIGA(LITHOGRAPHIE GALVANOFORMUNG ADFORMUNG):

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MEMS APPLICATIONS

BIOTECHNOLOGY

MEDICINE

COMMUNICATIONS

INERTIAL SENSING

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CZT (CADMIUM ZINC TELLURIDE)

Cadmium zinc telluride, (CdZnTe) or CZT, is a compound of cadmium, zinc and tellurium or, more strictly speaking, an alloy of cadmium telluride and zinc telluride.

The band gap varies from approximately 1.4 to 2.2 eV, depending on composition.

Cadmium Zinc Telluride (CZT),CdZnTe, is a semiconductor that directly converts X-ray or Gamma-ray photons into electrons.

It operates at room temperature and is capable of processing more than one million photons per second per square millimeter.

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CZT DETECTORS The role of a gamma radiation

detector is to capture any gamma ray photons which penetrate the crystal and convert this energy into electron-hole pairs that migrate to the anode and cathode at the top and bottom of the crystal. The resulting electrical signal is picked up at the terminals of the device which are connected to sensitive amplifiers and analysis circuitry.

FIGURE 7.1: NORMALIZED COUNTS VS ENERGY (KeV) GRAPH OF CZT

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CZT DETECTORS APPLICATIONS Very high count rate at room temperature makes CZT an excellent

detector for medical, security, astrophysics, and industrial measurement applications.

Medical applications include bone density measurements, nuclear medicine and probes for gamma-guided surgical procedures.

Security system applications strive to detect and identify radiation sources. Uses may be airport screening, first responders, or buildings with restricted access to radioactive sources such as hospitals and clinics.

There are a variety of industrial measurement applications for the food and beverage sector. These include the ability to accurately sense the level of liquids or solids within closed containers where optical inspection is not possible

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Thank You!!!