Tag Archives: bipolar

Society, Technology and Self — New Thin-Film Transistor

An engineering research team at the University of Alberta (U of A) has overcome significant challenges involving thin-film transistors (TFTs) that were faced by other researchers and the consumer electronics industry. They found a way around a problem that lead to their successes in achieving improvements in scalability and in power durability with their new thin-film transistor. The members of the U of A team are Gem Shoute, a PhD student, Doug Barlage, the electrical engineering professor, Ken Cadien, the materials engineering professor, and Triranta Muneshwar, a post doctorial fellow. They have all contributed to the creation of the powerful and new TFT technology and to the U of A article of this essay/summary.

The other researchers’ and the consumer electronics industry’s efforts to improve the performance of existing transistors and/or to create new transistor materials were not making much progress. They saw a physical attribute–a problem–with the traditional thin-film metal-oxide semiconductor field effect transistor (MOSFET) architecture, which they thought was inherent–unsolvable–, so they accepted this condition and did not try to make improvements on it, nor did they wish to tackle it.

The novel approach that the U of A engineering research team took was in finding an innovative way around the consensus problem by altering the design of the traditional MOSFET architecture, which improved its performance.

First, the article by U of A (2016) states that they overcame the daunting challenges of placing an ‘inversion’ hole layer in a ‘wide-bandgap’ semiconductor. This was a major breakthrough in the solid-state semiconductor industry, since: “[v]ariations […] from the transistor architecture have not been widely investigated as a result of the lack of available […] wide-bandgap inorganic semiconductors” (Shoute, 2016). In doing this they achieved the effects similar to that of a bipolar transistor, which incorporated the advantage of the bipolar function. The bipolar function incorporated two charge carriers, electrons (negative charge) and the absence of electrons (“holes” or positive charge), to contribute to the output of an electrical circuit. Most TFTs did not have this function. Their operation depended on a single charge carrier either with electrons or with the holes to contribute to the output of the electrical circuit.

Second, the first breakthrough allowed them to combine a unique set of layers with the semiconductors and the insulators, which enabled them to inject holes at the interface or “bipolar junction[s]” (Shoute, 2016) of the metal-oxide-semiconductor (MOS) layers. Metal is an electrical conductor, oxide acts as an insulator or dielectric [1], and the semiconductor depends on the direction of the flow of electrons for its operation. In other words, it only permits electrons to flow in one direction [1]. The oxide is layered between the metal and the semiconductor in a manner similar or analogous to a sandwich.

Injecting holes at the interface of the MOS increases the odds of electrons “tunneling” through the junctions. This tunneling effect was frowned upon by the other researchers and the consumer electronics industry, because it was viewed as a leakage of electrons that resulted in improper operation and an undesired electrical current or a loss in power efficiency. In actuality, this tunneling effect that was created by the unique injection of holes was the desired outcome.

The U of A (2016) article states that the engineering research team created a “quantum tunnelling phenomenon” that behaves similar to a bipolar transistor. The materials engineering professor, Prof. Cadien, stated in the U of A article (2016) that MOSFETs are usually constrained by the device’s “non-crystalline” physical properties. Shoute was quoted in the U of A article saying: “What we’ve done is build a transistor that considers tunnelling current a benefit[;]” and Prof. Cadien, was also quoted in the article saying: “It’s actually the best performing [TFT] device of its kind–ever” (University of Alberta, 2016).

This powerful and new TFT architecture can be very easily reduced in scale to improve performance and to keep up with the miniaturization trend of technology. This ability of scalability is not possible with the traditional MOSFET architecture. This new TFT is much more durable in electronic circuits, because it can withstand at least 10 times more power than current commercially produced TFTs, without experiencing failure in functionality or being destroyed.

This new technology may lead to enhanced capabilities with flexible electronic devices, with renewable energy and medical imaging applications, with other various display technologies, and the list can go on and on. These new TFT devices will be able to bend and fold in various ways without breaking, which will make them more durable. They will enable flexible devices to create new applications, such as 3-D displays that simulate holographic projections. They will be able to be manufactured much smaller, leading to relatively less consumer waste and being relatively lighter to transport. They will be more energy efficient by consuming relatively much less power. They will have enhanced performance in high speed switching and in high frequency applications. They will be more sensitive; therefore, more efficient in information and data communication and more precise in detection and actuation implementations; for instance, less intense X-rays would do the same job as that which is performed by more intense X-rays in use in medical facilities today.

This powerful and new TFT has opened the door to possibilities that were previously only a dream in someone’s mind or the fantastical imagination of fiction writers. Who actually knows where this new technology will lead to next? We can only predict our future, but there are still possibilities that have not even been thought about before. All it takes is a step in the right direction, one innovation or invention to lead to another. This is the principle of cause and effect that is so very important to societies’ and cultures’ technological improvements and advancements that there would not be any of the breakthroughs that we take for granted today without the previous innovations and inventions.

Footnote
1. This is normally the case, with Zener diodes as the exception. Zener diodes are a special type of semiconductor. At a specified electrical voltage threshold, Zener diodes permit electrons to flow in the direction that another type of semiconductor would not allow. (A more precise description would use the word “overflow” instead of “flow,” which is analogous to water overflowing at the edge of an already filled container, as more water is added to it. Here water represents the electrons.) I have a bachelor degree in electronics engineering technology (B.E.E.T.).

Annotated Bibliography
American Institute of Physics. (2015, June 30). Biodegradable, flexible silicon transistors: Biiodegradable silicon transistor based on material derived from wood. ScienceDaily. Retrieved May 15, 2016 from www.sciencedaily.com/releases/2015/06/150630121206.htm
This article describes the new biodegradable thin-film transistor (TFT) wood material that is low cost and can be used in portable electronic devices. The article explains that discarded electronic devices made from this material will not be harmful to the environment. Fungi decompose the transistor. This article provides the benefits from the use of this new technology for the future health of the environment and with “superior performance” in comparison with silicon based transistors. This new technology was created by researchers at the University of Wisconsin-Madison.

Carney, R. (2016, February 9). Faculty of engineering: Media centre. University of Alberta. Retrieved March 9, 2016 from http://www.engineering.ualberta.ca/en/MediaCentre.aspx
This is one of many sources that will establish the credibility of one of the researchers who is directly involved with this research project. His contact information is available for inquires. This will be an invaluable asset to be utilized with my research paper.

National Institute for Materials Science. (2015, January 23). Improvements in transistors will make flexible plastic computers a reality. ScienceDaily. Retrieved May 15, 2016 from www.sciencedaily.com/releases/2015/01/150123081213.htm
This article states that researchers have newly developed transistors that can be used to create “flexible, paper-thin computer screens.” The scientists at conducted research on organic field-effect transistors (OFETs) that have light emission and detection and amplification physical properties. This article also describes future uses and improvements on this new technologies, such as faster response, relatively lower energy consumption, better efficiency, etc. This article is relevant to my topic about transistors and their future applications and implications.

North Carolina State University. (2014, November 13). New way to move atomically thin semiconductors for use in flexible devices. ScienceDaily. Retrieved May 15, 2016 from www.sciencedaily.com/releases/2014/11/141113085222.htm
This article describes the development of a new technique for transferring atomically thick semiconductor films onto arbitrary substrates (layers/surfaces). The North Carolina State University researchers developed a technique that is much faster and is not prone to cracking the film. This article relates to my research by providing information about flexible, thin-film semiconductor materials and manufacturing technologies. Currently, the material is too hot during manufacturing to be placed on a flexible substrate; however, the researchers have overcome the problem in which it was too delicate for transfer. Their techniques uses water, tissue, and tweezers.

Shoute, G. et al. (2016, February 4). Sustained hole inversion layer in a wide-bandgap metal-oxide semiconductor with enhanced tunnel current. Nat. Commun. 7:10632 doi: 10.1038/ncomms10632 (2016). Retrieved March 9, 2016 from http://www.nature.com/ncomms/2016/160204/ncomms10632/full/ncomms10632.html#close
Although this secondary source is from a “dot-com” website, it is listed at the bottom of the original ScienceDaily article as the “Journal Reference,” which gives credibility to it. It contains a more detailed description about transistor technology. Learning about this type of technology detail will add more competency to my general understanding, and it will allow me to analyze and examine this new thin film transistor in more depth. Shoute, G. is also the University of Alberta, PhD student who is one of the lead authors involved with the “New Thin-Film Transistor” breakthrough article that is the focus of this essay/summary.

Technical Research Centre of Finland (VTT). (2014, June 18). New printing method for mass production of thin film transistors. ScienceDaily. Retrieved May 15, 2016 from www.sciencedaily.com/releases/2014/06/140618071741.htm
This article describes the new process for manufacturing thin-film transistors (TFTs) that was developed by scientists at the Technical Research Centre of Finland. This new “roll-to-roll” technique will allow for more applications and it will reduce the cost to manufacturers. This article directly relates TFTs to being ideally suited for flexible, thin screen display applications, which was only an inference in other article that I have read. This article has also directed related TFTs as being better suited to “large-surface” displays and other details which provide confirmation and verification to information in the other articles that I have read concerning my research.

Tung, Y. (2016, February 9). Thin film transistor technologies. Berkeley EECS. Retrieved March 9, 2016 from http://www.eecs.berkeley.edu/~tking/tft.html
This source will provide more details about thin film transistor technologies which will provide a more thorough understanding about the limits and capabilities of transistors that are currently in use and other projected breakthroughs regrading this topic. Note: This article does not have a direct title for the publisher, such as a name of a magazine; however, it is related to the Electrical Engineering and Computer Sciences department at Berkeley and a grant from the National Science Foundation.

University of Alberta. (2016, February 9). New thin film transistor may lead to flexible devices: Researchers engineer an electronics first, opening door to flexible electronics. ScienceDaily. Retrieved March 9, 2016 from https://www.sciencedaily.com/releases/2016/02/160209162412.htm
This source is the first detailed description pertaining to my research topic. It is the basis for my general understanding about the subject matter and for acquiring leads for related information. It also lists the key researchers and their institution, which will contribute to the credibility of the new technology. Note: Reference to this University of Alberta article source is indicated by the abbreviation of “U of A,” as it is abbreviated in the original article.

University of Massachusetts Amherst. (2015, May 5). Improving transistors that drive flexible electronics. ScienceDaily. Retrieved May 15, 2016 from www.sciencedaily.com/releases/2015/05/150505131753.htm
This article investigates the performance capabilities of organic flexible transistors (thin-film transistors–TFTs) under flexing. It describes the low temperature flexibility of organic transistors, as opposed to high temperature rigid inorganic silicon transistors, which makes them ideal for flexible electronics being manufactured today. The low temperature quality makes easier and cheaper to manufacture. The UMass Amherst researcher, Reyes-Martinez, states that mechanical deformations do not always cause improper operations of transistors. In some instances, the performance can be enhanced or not be affected by deformations. This article helped me to better understand the progress made within the TFTs industries and their future applications.