Click on the course name to go to the particular section-
- EE541 Solid State Sensors
- EE548 Microelectronic Device Fabrication
- EE559 Semiconductor Device Physics
- EE598 Individual Problems Course with Dr. Peter Liu
EE541 Solid State Sensors
I had the fantastic opportunity to be enrolled in Dr. Jim P. Zheng’s class for EE541 Solid State Sensors during my time as a graduate student in the Electrical Department at University at Buffalo. The course offered insight into various fabrication technologies for semiconductor sensor devices and their applications. Since I wanted to pursue a career in the semiconductor field, the course curriculum suited my academic desires well. The course, Solid-state Sensors, provided me with a chance to learn about different types of sensors- mechanical, acoustic, thermal, chemical, and biological. It introduced me to possible industries I could work in in the future as an Electrical Engineer. Each class followed a well-designed structure, starting with the theoretical understanding of the sensor type we are learning, then focusing on the operational principles and industry applications. Dr. Zheng provided me with enough resources to connect the dots between the course curriculum and its practical applications in industries.
Besides written examinations and homework assignments, the majority of the grading for the course involved a final project submission. We were encouraged to choose any topic about an industrial application of the sensor types we learned in the class. I chose the research topic- “Use of piezoelectric devices in an automotive industry.” The piezoelectric phenomenon works on the principle that certain materials convert mechanical forces into electrical energy. I investigated and researched various aspects of this phenomenon in developing systems in the automotive industry. Automotive systems such as Piezoelectric fuel level sensors, knock sensors, fuel injectors, and tire pressure sensors make use of the piezoelectric or converse piezoelectric phenomenon. The converse piezoelectric phenomenon means utilizing electrical energy to develop mechanical forces in certain materials (natural as well as artificial).
My final project allowed me to witness how the engineering of solid-state devices could help improve fuel economy, safety and provide compact, low-power, and reliable applications in the automotive industry. Working on the project improved my research skills and enhanced my understanding of various systems in the automotive industry.
I believe that if you want to correlate your course learning and its industrial importance, the course, Solid State sensors, is a fantastic choice. Instead of focusing on just one type of sensor, this course covered an introduction to most sensor types. Dr. Zheng motivated us to select the industry we are passionate about and find applications for the various sensor types in that industry. I am grateful for such a unique opportunity to learn, research, and expand my industrial understanding of solid-state devices. I would encourage others to take advantage of this course.
EE548 Microelectronic Device Fabrication
The Microelectronic Device Fabrication course played a vital role in solidifying my interest in the semiconductor industry. The learnings from this class benefitted me in my job interviews. They were crucial to my success in securing an internship at Applied Materials- one of the largest semiconductor chip manufacturing industries. Dr. P-C Cheng’s Microelectronic Device Fabrication class had a unique class schedule and format. We only had one lecture per week. But it was a three-hour class. Also, for grading, we had one final project presentation and submission. The structure of every lecture was designed in a way that would answer any queries we would have in completing the final project.
For the final project, I worked in a team of 3 to develop a NAND gate IC from the given NAND gate circuit diagram. NAND gate is considered an important discovery in modern electronics as it is regarded as a universal gate with a unique capability to create all other logic gates.
We also used circuit designing tools such as Altium and Proteus to perform our circuit simulations. We verified the designed circuit’s operation by comparing the simulations to the Truth Table for NAND gate.
We designed and tested simulations of simplified versions of a NAND gate circuit and compared its economic superiority for production with the given NAND gate circuit. First thing we considered was the simplicity of the circuit in terms of components used. The project also challenged us to think about the business aspect of the semiconductor fabrication industry. The challenge encouraged us to look for out of the box ideas and design strategies to make our IC manufacturing more efficient. We finalized the diagram number 2 as it had minimum number of different components required to manufacture a NAND gate IC compared to the original design and the designed diagram number 1.
A majority portion of the project involved understanding photolithography steps to create transistor and resistor circuits to design the NAND gate circuit. It opened a door for me into the exciting field of lithography engineering as a future career option.
The following diagram explains the steps involved in a photolithography process. This project starts with the Si wafer substrate. Then, this substrate material undergoes oxidation, applying photoresist, mask overlaying, and etching process. Then, diffusion of ions is done to create ion wells in the substrate material.
Following diagram depicts the final photolithographic circuit design for a NAND gate with two NPN transistors and 3 resistors. To create each component, a set of steps of lithography process take place.
Dr. P-C Cheng provided us with the freedom to tackle this problem however we like. He created an encouraging learning environment to discuss the objective with other groups, learn various approaches to the same problem, and learn from each other. We learned about various processes involved in creating an integrated chip. We started by learning about processes for silicon wafer manufacturing, contamination control, Photolithography, and patterning. It provided a start to end, a complete dive into the fabrication of semiconductor chips. Engaging in classroom lectures and working on this project made a fulfilling educational experience.
EE559 Semiconductor Device Physics
After my Bachelors in Electronics Engineering, I had decided to continue my academic career in the Solid-state Electronics field. So, when I was looking at the course catalog for my first semester at UB for graduate studies, I knew I wanted to take the course Semiconductor Device Physics taught by Dr. Vasili Perebeinos. The course was my introduction into the field of semiconductors. It equipped me with the physics necessary to understand why semiconductors work the way they do. The learning experience in this course was very unique for me as the class makeup consisted of one Ph.D. student, two Masters students, and one undergrad. The classroom environment was very accommodating and due to a smaller class size, lectures felt similar to group discussions and we had the opportunity to clarify our doubts whenever we had them.
The course started with understanding the evolution of electronics and computing. Lecture discussions involved display of different semiconductor materials used to achieve this evolution and recap of basic operations of a typical FET, MOSFET with their I-V characteristics. At the end of the first lecture the professor mentioned various device metrics such as on- current, off- current, sub-threshold swing, transconductance, threshold voltage, etc. and mentioned that our primary objective of the course would be to understand these metrics and their effects in the semiconductor devices. So, my goal for the course was clear from day one.
The subject was definitely challenging and required understanding of Mathematics, Physics, and a little bit of Chemistry as well. Home-work assignments were based on the concepts from lectures and discussions. Also, we had surprise quizzes every week, based on the lecture topics studied that week. So, active participation in the group discussions was essential to not fall back on the subject matter.
The course had a final research project requirement and we all had the freedom to propose the topics we want to work on. I wanted to bring my python programming skills to the field of semiconductor physics, so I proposed a project where I would create a program which given some input metrics of the MOSFET device, could predict the ideal and non-ideal behavior of that device. My idea was accepted for the final research project. I was trying to bring three different fields- programming, semiconductor device behaviors, and user interface design together through my project. It kept me motivated throughout my project work. I received constant support and feedback from Dr. Perebeinos for my project.
The program I created provided two options for the users. First was to observe the ideal behavior of the device under consideration by creating various graphs such as Id vs Vds (Drain current vs Drain to source voltage), gm vs Id (Transconductance vs Drain current), and Id vs Vgs (Drain current vs Gate to source voltage).
Second was to observe the non-ideal behaviors of the device under consideration. For non-ideal behavior, I considered three phenomenon- the body effect, Subthreshold conduction, and channel length modulation. The project helped me achieve the primary objective of the course, which was to understand various semiconductor device metrics and their effects on its behavior.
I would definitely consider this graduate course as one of my most challenging and academically essential at UB. It has motivated me to pursue higher education as a Ph.D. student, investigating semiconductor technologies. I learned how to successfully combine various skills together within a research project. I have no doubt that this course will prove beneficial for my future academic career. I would encourage students who want to specialize in solid state electronics to definitely enroll in this course.
EE598 Individual Problems Course with Dr. Peter Liu
During the Spring of 2022, I worked with Dr. Peter Liu in his research Group “Mid-infrared and Terahertz Photonic and Opto-Electronic Lab (MT. POET).” Working in the lab on various projects with other research group members was one of the best experiences of my masters. It motivated me to pursue higher education in a Ph.D. program. For the entire duration of the Individual Problem Course, I worked with Aarbaj Mundaganur, another master’s student from the EE Department. We would perform experiments, prepare group presentations, and deliver them in biweekly meetings with other research group members. Dr. Peter Liu created a nurturing educational environment for all group members. We learned from each other’s research activities.
I was part of two research projects in the MT. POET research group. The first was investigating various methods to reduce surface roughness in metal films. Aarbaj and I had to review many research papers for the literature review. It was an exciting activity as our job was similar to detectives trying to find a link from the clues of these research papers. I would say, working on this research project significantly improved my literature review skills. We found two primary ways of reducing surface roughness in metal films. First, optimizing the process used for metal film fabrication and changing parameters that help improve the surface roughness. Next was to utilize new methods developed to create smoother surfaces. One such method is Electromigration. It involves applying a high-density electric current on a metal film’s surface to cause a movement of atoms on the metal film surface.
Another research project we worked on involved bio-mimicking for photonics applications. Bio-mimicking means taking a good design from nature and utilizing it for our objective. We worked with Diatomaceous earth; a fossilized remnant of unicellular photosynthetic organisms called Diatoms. There are 100,000 species known worldwide, found near any water body. What makes it extraordinary is its outermost shell, made up of silica. Their structure is microscopic, highly symmetrical, and beautiful. No wonder they are recognized as the “jewels of the sea.”
We separated these diatom samples into different sizes and tried to coat them with Graphene flakes. We produced Graphene flakes solution by using an ultrasonic bath machine. It exfoliated a graphite block into Graphene flakes. We experimented with different solvents and times for sonication process to produce the desired quality of Graphene flakes. And to observe the results, Ph.D. students from the research group helped us acquire SEM (Scanning electron microscope) images of the sample under experimentation.
We also used the FTIR measurement technique to characterize the Diatom materials, Graphene flakes, and Diatom- Graphene flakes mixture. We observed a change in the optical properties of the mixture samples from the original material. It proposed possibility of potential applications of these materials in photonics world.
The Individual Problem Course with Dr. Liu was one of my favorite courses during my MS degree. I would encourage every student to take part in such individual problem courses. They allow you to work on entirely new research projects or support current Ph.D. students in their research activities. This course made me realize how fun, challenging, and satisfying research work can be. I am grateful for such an amazing educational blessing.