Author: Hannah Bylak        Major: Electrical Engineering and German

Probing the Transistor Device for Characteristic Measurements

My third semester of college here, I took digital design with Dr. Chen. It was fascinating to see how much could be controlled by funneling ones and zeros into logic gates. Logic gates interpret inputs and, based on how the internal circuits are set-up, will output either a one or zero. Think about it as if you’re deciding to buy a chair; a yes is a one and a no is a zero. If you’re buying a chair, you want it to be comfortable and look nice. One chair is comfortable, but is not stylish. Using an AND logic gate (because you are looking for both comfort and style in a chair), you’d get a zero for style and a one for comfort. The AND logic gate would see that both comfort and style aren’t present, so it would output a zero. This zero represents a no, so no you would not want to buy that chair. There are several types of logic gates besides the AND gate, but what differentiates the operation they use is the internal circuit made up of transistors.

Much like cells to a living organism, transistors are the basic building blocks to many electronic parts. Because they are so fundamental, it’s important to characterize them to define and extend their application limits. To use them in harsh environments (such as high temperatures in cars) the transistor must be built to sustain itself. This past semester in neural network circuit design, we used only transistors to simulate how the brain communicates. Upon realizing how vast the range of application for transistors is, I decided to do my project on characterizing them.

The first step to designing a transistor would be to know the characteristics that can be changed, and how those changes affect its function. This project required a lot of expansive background knowledge. Not only did I need to draw from old class notes and textbooks, but I also had to read scientific papers and textbooks for classes I have yet to take. There was a plethora of technical terms and acronyms to memorize. This is where working with my professor, Dr. Chen, and his research group came in handy. After I had read up on the fabrication process, I was able to attend a lab session in HiDEC where the other students were fabricating parts of transistors. I was also able to attend weekly meetings where I listened to the other students in Dr. Chen’s group present on the individual aspects of transistors that they were studying. The other students also helped train me in using various equipment in the lab at Cato Springs Research Center, so that I could understand how to gain measurements. In the end, I learned a lot about different testing set-ups, transistor aspects, and theoretical equations.

In the future, I hope to apply what I’ve learned about transistors to other projects. I’m now more familiar with what limits transistors regarding materials and voltage levels, which I can apply to the senior design project I’m working on. Not to mention, my senior design project will be using new biosensors. Those sensors will need to be characterized and adjusted in order to properly apply them, just like the process for characterizing transistors. The skills I learned to breakdown theoretical equations for measurements will also be useful in any field, not just for electronics projects.