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ECE340

ECE340 (Semiconductor Electronics) is a 3-credit-hour course that is specifically required for EEs as part of the Electrical Engineering Core and satisfies the 1-of-6 Electrical Engineering Foundations Course requirement for CEs. It is offered in the fall, spring, and summer.

Content Covered

Intro Semiconductor Theory

  • Band diagrams
  • Fermi-Dirac/Maxwell-Boltzmann Statistics
  • Drift and Diffusion of Carriers
  • Carrier lifetimes and Photoconductivity

Basic Devices

  • PN Junctions
  • Optoelectronic Devices (Photodetectors, Solar Cells, LEDs, LASERs)
  • Metal-Semiconductor Junctions

Advanced Devices

  • MOSCAPs and MOSFETs
  • BJTs

Much of the theory discussed in ECE340 can be traced back to discoveries made in ECE at Illinois. The material in ECE340 is cumulative in a very clear-cut manner; new topics build on previous topics continuously in the course. In the beginning, students are introduced to semiconductor physics with crystal lattice structures, doping, energy band diagrams, and carrier drift and diffusion. These topics form the theory and math needed to cover the next section of p-n junctions and diodes. P-n diodes are then used in understanding the physics behind bipolar junction transistors, metal oxide capacitors, finally metal-oxide transistors, the last topic covered. While the class is heavy on math, the testing structure is set up such that one needs to understand the concepts behind each equation. Therefore this course is similar to physics courses in that it is essential to have an understanding of the theory and not just the math. In fact, part of the conceptual understanding involves recognizing when various approximations can be made that simplify analysis and calculations. This includes the effects of heavy doping or ignoring the effects of recombination of carriers.

Prerequisites

Officially PHYS214 is listed as a prerequisite, while ECE329 is listed as a pre-/co-requisite. ECE340 involves many physics concepts such as diffusion and particle distribution, so having completed PHYS213 is almost as important as PHYS214. In fact, several PHYS213 lectures cover semiconductor physics at a basic level. The first part of ECE340 will involve various topics from PHYS214 such as the concept of discrete energy levels, and a brief discussion of Schrödinger's Equation and its consequences in semiconductors.

Relevant topics from ECE329 include Maxwell's equations in material media and carrier mobility. They apply in ECE340 to topics such as p-n junctions and carrier flow, but should be covered early enough in the semester if taken concurrently with ECE 340. Overall, these courses are most helpful in developing an intuition for what is happening at the physics level inside electronic devices.

When to Take it

Taking this course in accordance with the stated prerequisites and corequisites is especially important for ECE 340, due to its emphasis on conceptual understanding. Because of the overlap with physics concepts, it is best to take this as soon as possible after the prerequisites. This course is a gateway to many other courses in electrical engineering such as electronic circuits and IC fabrication, and in physics. It is beneficial for students considering careers in anything to do with physical and quantum electronics and circuits to take ECE 340 as early as possible. For those who wish to take this course as early as they can, this can be taken concurrently with ECE329 as soon as junior eligibility is achieved (completed all of the required 100 and 200 level courses).

Course Structure

The course's structure is fairly standard with a combination of 11 homeworks, 2 midterms, and a final.

Homework assignments are assigned each week and usually consist of three or four problems that may involve drawing band diagrams, derivations, calculations, conceptual explanations, or using an online semiconductor simulation applet. There will be multiple times where certain assumptions must be made (temperature independence, neglecting a small concentration, etc) to make certain problems solvable in a reasonable amount of time. This can be frustrating for students used to solving problems with the exact parameters given to them, but making and justifying these assumptions are part of the course.

Midterm exams for ECE340 are quite infamous among the 300 level ECE courses. While slight logistical things can vary between semesters (you may or may not see the exam equation sheet before the midterm), in general the tests are 3 questions with several subparts to be solved in 1 hour without a calculator. They are usually even more of a test of time management than ECE210 exams. The strangest quirk about this course is the lack of access to past exams. The testing format also means that there is little similarity to homework problems. This structure makes understanding the concepts taught in ECE340 paramount to success.

Instructors

Prof. Leburton is the course director. Professors that have taught ECE 340 in the past include Prof. Rakheja, Dragic, He, Zhu, Dallesasse, Bogdanov to name a few. Most professors who teach this course specialize in device physics or nanoelectronics.

Course Tips

Try not to get discouraged when receiving grades back, this is set up to be a tough course and your overall grade does not fully reflect your ability to work with semiconductors.

Partial credit on exams is your best friend. If a problem is too challenging, write down as many equations or notes that seem adjacent enough to the problem and the graders may reward it.

ALWAYS justify an assumption. It is required to complete a problem, but also a good check to make sure the assumption is valid.

Life After

Not surprisingly, ECE340 is the prerequisite to many courses in the area of solid-state electronics, including ECE441 - Physics and Modeling of Semiconductor Devices, ECE444 - Theory and Fabrication of Integrated Circuits, and ECE482 - Digital IC Design. Taking ECE342 - Electronic Circuits either before, concurrently, or after ECE340 provides a good overview of electronic circuits at both the device and circuit levels.

Infamous Topics

  • The whole class (But this is true for everyone, so the curve will save you.)
  • PN Junctions (Keep track of subscripts, the variable is WHAT is described and the subscript is (usually) WHERE it is)
  • MOSFETs (These could be a whole class, and are usually the last thing you learn as you rush to finals - STAY VIGILANT, YOU'RE SO CLOSE)

Resources

nanohub.org is run by those scumbags at Purdue, and unfortunately it is one of the best semiconductor resources ever created. Not only does it have amazing introductory videos and lectures, it also has a built-in simulation tool to get a "hands on" understanding of semiconductors.

THE TEXTBOOK IS YOUR FRIEND - Lectures jump around the textbook, and it is a fantastic resource to get a better feel of some of the proofs/math that they skim over/don't have time for in class.