[MUSIC] Welcome to introduction to semiconductor device. My Name Is Keon Jae Lee, I'm a professor at Department of material science engineering in KAIST, located in South Korea. This course is based on the textbook, Solid State Electronic Devices,7th edition by B.G Streetman, Prentice Hall. And objective of this course is, to teach the physical operating mechanism of semiconductor devices, carrier transport in semiconductor, pn junction, metallic semiconductor junction, MOS capacitor, bipolar junction transistor, MESFET and MOSFET. I recommend you print my lecture note, and there will be seven homework and midterm and final. This is the course schedule. First week introduction to semiconductor device overview, history, industry and market. Second week crystal properties, such as the atom, electron, Schrodinger equation. This material is labelled with a quantum mechanics, solely the state physics, and crystal log p. However, this is not directly related with a semi-conductor device. We'll briefly overview those material. Even though you don't perfectly understand these crystal property, you don't have any problem understanding semiconductor device. Lectures three is starting point about semiconductor device, which is carriers in semiconductors, and lecture four, drift and excess carrier. Excess carrier is one of the most difficult and important part of the pn junction. Lecture at week five, we going out carrier transport, drift and diffusion and sixth week, pn junction. And then midterm. As you can see, pn junction is almost half of the total courses, that much pn junction is important in semi conductor device. After pn junction, we will study the breakdown mechanism, metal semiconductor contact and MOS Capacitor. MOS stands for metal oxide semiconductor. And then we learning MOSFET metal oxide semiconductor field effect transistors. After we learn the MOSFET until the 12 week, then we moved to the integrated circuit CMOS logic and process, 14 week, MESFET, memory,modern MOSFET and optoelectronics. Finally, we're going to learn BJT and then final exam. This crest is mostly focused on the theory and calculation. Related class is, as I said, quantum mechanics, solid state physics and crystallography. However, if you don't know detail, about the crystal property, it's not main focus of this class. So you don't have any problem understanding device. And then before the midterm and after the midterm, we dealing with this devices. Course overview. What is the purpose of this class? I said The purpose of this class is understanding MOSFET device. MOSFET is metal-oxide semiconductor field effect transistor. This is the driving force of the modern digital semiconductor technology. What is the MOSFET? MOSFET is the structure as shown in the right image. They have all gate over the metal, below the metal there so gate oxide and then there's a P type silicon semiconductor. Besides of metal, their source of M plus doping and drain of the M plus doping. So this MOSFET, determines digital one and zero of the digital era. If it switches on, then digital one switches off digital zero. This is similar to the faucet of the water flow, if faucet is open, water flow, then turn transistor then digital one. It for faucet is closed and water is stopped, then transistor is off, digital zero. The law of the faucet is done by metal oxide semiconductor capacitor, which is similar to the faucet. More detailing, if gate is above the threshold the voltage, then faucet of the MOS is open and transistor on, this is digital one. If gate voltage is zero, then faucet is closed, transistor is off, and digital is zero. This is all about this class about the MOSFET that we are going to learn. And then I will comment on two things. If you look at these MOSFET structures, there is 2 pn junction because p type semiconductor and m plus source region, p type semiconductor and m plus drain region. So MOSFET is consistent with a 2pn junction. That's why I can say that, MOSFET also comprised with the 50% of pn junction, then much pn junction is important. Second, then what is the semi conductor? So there is a conductor, insulator and semi conductor. So conductor is current always flowing. Insulator current is not flowing. Semiconductor, in some condition current is flowing and transistor on, in some condition current is not flowing. So that's why it called semiconductor, which can drive digital data of both one and zero.