6N8398 Introduction To Computers

Introduction

MEMS is an acronym of Micro-Electro-Mechanical Systems (Santos, 1999). It is composed of microscopic elements such as Mechanical, Sensors, actuators, electrical and electronic devices which are embedded on a common semiconductor preferably Silicon (Design guide, 2017).  The system has found wide applications in various industries as it enables tiny pieces of work to be manipulated without difficulty.

Some of the MEMS useful in various industries include: the adaptive optics for ophthalmic applications, Optical cross connects, airbag accelerometers, mirror arrays for television and displays, high performance steerable micro mirrors, disposable medical devices, high force, high displacement, electrostatic actuators and secure communication systems (Design guide, 2017).

Generally, the operation of MEMs involves the following: the sensors gather information from the environment through measuring mechanical, thermal, biological, chemical, optical, and magnetic properties (Banks, no date). The electronics part picks up the signals, carries signal amplification and proper decisions are made in the microchip. The information is processed as per the signals perceived from the surrounding. Thereafter, the actuators are directed to produce appropriate action such as moving, positioning, regulating, pumping, and filtering among others. Hence the system can effectively control parameters such as temperature, volume flow among others. Normally, the normal sizes of MEMS range from 1 to 100 micro meters (Angel, no date).

According to design Guide (2017), MEMS can be applied in the following areas:

• Airbag systems- it utilizes the inertial sensors such that the accelerometer monitors the acceleration of the car. When a large change in velocity is detected by the microcontroller, the airbag is automatically flashed out. The response is more reliable than with the traditional airbag control systems.  
• vehicle security systems
• Intertial brake lights
• Head light leveling
• Rollover detection
• Automatic door locks
• Active suspension

And lastly, MEMs can be used to: detect Earth quake and gas shut-offs, machine health and shock and tilth sensing.

Integrating Mems Into The Application –Biomedical Application

As mentioned in the introduction, MEMS have several applications in different industrial sectors. Besides, they have the following common features:

• Micro- describing the miniature size in the range of nanometers to micrometers
• Electro- This is the electronic part. It comprises the electronic signals processing and flow. It also has the portion that does the sensing. The electronic part also makes intelligent decisions and interacting with the immediate environment (Wen, 2012).
• The mechanical portion –It comprises the physical structures, the actuators and the integrated controls and communication systems which are embedded on the MEMS architecture (Wen, 2012).

Biomedical Applications

The MEMS which are used in this case are the inertial sensors. The common types include the accelerometers and gyroscopes (Wen, 2012). They are useful in specific biomedical applications such as making the hearing aids transducers and the inertial sensors.

• MEMS Hearing Aids

Majority of old people have problems with hearing. They need artificial devices to help them in hearing. However, the traditional hearing aids have been tied to social stigma leading to reluctance in their use. The MEMS hearing aids are therefore gaining traction and therefore replacing the traditional ones. The aid has an electro-acoustics device used to receive, amplify and radiate sound into the ear. Hence it is designed to compensate for the patient’s hearing loss. Therefore, due to miniaturization, hearing aids can be used easily by these patients without suffering any social stigma ( Ramesh, 2013).

• MEMS Inertial Sensors

The accelerometers and gyroscopes are used to make unique wheel chairs (Ramesh, 2013). It works on a combination of multiple inertial sensors to operate and lift the wheelchair. Hence the wheels can be balanced vertically. 

Comparison with other Methods

The MEMS are still evolving across many industries hence it is still at an infantile stage as it is yet to experience the explosive growth as was the case with the integrated circuits in the 1970s. But, curiously, how do MEMS compare with the ICs? Firstly, ICs have got more mature technologies than the MEMS (Ghaffarian,2000). They are completely different technologically. Besides, MEMS present unique challenges in packaging and integrating into the device system (Ghaffarian, 2000). Designers are always aiming at creating a balance between protecting the delicate MEMS and allowing it to interact with its surrounding, for instance, when sensors are designed to pick the temperature readings of a room, a portion of the system will have to be exposed to space but in some cases these would introduce outside interference into the system hence affecting the performance of the MEMs. Hence their packaging is made more complex than the ICs (Ghaffarian, 2000). Materials used to make the MEMs must therefore have the ability to withstand the various stresses during handling and operation. Additionally, the packaging materials should be resilient to the vibrations that occur during operation. Secondly, the MEMS are also being made to easily integrate with various microelectronic components. This is usually done by embedding them in the same chip, that is, in the same wafer level to produce better electrical output (Ghaffarian, 2000).

Furthermore, how reliable are MEMS in comparison with the ICs? MEMs reliability for various systems can be very different. Standardized reliability testing is therefore not possible. However, some of the reliability issues of concern, according to Ghaffarian(2000), include: tribological behavior, contamination, cleaning stiction, and typical fatigue issue. For instance failure by stiction and wear is of great concern to the designers. Failure can occur as a result of microscopic adhesion when two surfaces come into contact. Hence, the engineers’ selection of materials takes into consideration such aspects to ensure higher reliability of the micro-devices. 

The Limitations of using MEMS devices in the mentioned application include:

The MEMS are useful in many applications. However, they have got limitations such as:

• The high voltage is required for small deflection
• The system may also suffer slow response
• The process is complicated requiring harmonious function of different components.
• The slow response can also be irreversible making the system to potentially be phased out in the near future thanks to the rapid technological breakthroughs in this area.

However, there are number of potentials applications in the agricultural industry. In the dairy farming, the technology has a great potential such that it can be used to detect mastitis in lactating cows. According to Photonics Media (David et al, 2008), the mastitis disease costs the US dairy industry between $184 and $200 per cow. Besides, the detection methods existing are slower hence MEMS can offer realtime detection saving the farmer time and cost of detecting the disease.

 Therefore, the technology can be useful in immobilizing the mastitis pathogen, that is, E.Coli. Normally the capacitor of a reference sensor and that of a functionalized sensor are compared. If the capacitances differ, then the pathogen is present.

Other potential applications include:

• Hyperspectral imaging useful in detecting fungal diseases in crops
• In packaging and refrigeration to offer real-time storage of food (David et al, 2008)

The limitations of using MEMS/MEMS devices in the application:

Although the technology has several advantages over other methods, it has some limitations in its application and such include:

• Firstly, MEMS differ largely with existing technologies making it disruptive to other existing methods hence the reluctance to its use (Kovacs, 1997).
• It also experiences challenges in developing manufacturing processes to make the MEMS
• Due to technological bottlenecks in foundries, MEMS have not gained wide acceptance in this industry
• The market of the device is also uncertain thanks to its infantilism

However, some of the advantages of using MEMS include:

• Due to its small size, that is, its mass and volume , it can be used over an array of applications easily
• It also consumes less power making an energy efficient device
• It can also easily integrate in  various systems
• It has a small thermal constant
• Highly resistant to vibration shock and radiation
• The batches can be fabricated in large scale and automation is possible making the components manufacture rapid
• And lastly, it has improved tolerance to temperatures.

Conclusions

MEMS continue to be the major scientific and technological breakthrough across all industries. The field of nanotechnology promises to resolve various problems facing different industries.  Virtually across all industry sectors, nanotechnology is developing at a rapid rate with great promise of revolutionizing the sectors.  However, the technology is still a work-in-progress(Feyman, 1992). Specifically, researchers are making positive attempts to fine-tune the MEMS sensors by ensuring excellent matching with the actuators (Muller et al, 1991). The circuitry is being relooked and redesigning of the same to include high quality matching and signal processing capabilities hence providing excellent actuation response. Hence, with that kind of breakthrough, some of the teething problems of the technology can be resolved. Notably, however, MEMS will continue to be part and parcel of our technology drivers like the way computers are seemingly promising to stay with us forever and ever!

References

Design Guide. (2017). Introduction and application Areas for MEMS. Available at: https://www.eeherald.com/section/design-guide/mems_application_introduction.html

Wen,L.(2012).MEMSforBiomedicalApplication.OnlineNotes.Available at: https://www.egr.msu.edu/classes/ece445/mason/Files/BioMEMS_Guest%20Lecture_WenLi.pdf

Angell, J.B...et al. (no date).Silicon Micromechanical Devices. Scientific American.

Banks, D.(no date).Introduction to Microengineering. Available at: https://www.dbanks.demon.co.uk/ueng/ what.html

De Los Santos, H.J. (1999). Introduction to Microelectromechanical (MEM) Microwave Systems. Artech House Microwave Librar. Boston, MA.

 Feynman, R.(1992). There’s Plenty of Room at the Bottom, Journal of Microelectromechanical Systems. Vol.1, No.1, pp. 60-66.

Kovacs, G.T.A.(1997). Fundamentals of Microfabrication. CRC Press Inc .

 Muller, R. et al. (1991). Microsensors, IEEE Press, New York. Trimmer, W.S., Micromechanics and MEMS: Classic and Seminal Papers to 1990, IEEE

David, R &David, A. (2008). MEMS Technology Tackles Food and Agriculture Challenges. Online notes. Available at: https://www.photonics.com/Article.aspx?AID=32591

Ghaffarian, R. (2000). Comparison of IC and MEMS Packaging Reilability Approaches. California Institute of  Technology. Avialable at: https://trs.jpl.nasa.gov/bitstream/handle/2014/15846/00-1618.pdf?sequence=1&isAllowed=y

Ramesh, R. (2013). MEMS Devices for Biomedical Applications.California. Available at: https://electroiq.com/blog/2013/10/mems-devices-for-biomedical-applications/