MOSFET || KTU || ECT 202 ANALOG CIRCUITS

Hi all, today we are starting our third module. In this third module, we are going to learn about MOSFET Amplifiers, Cascading Amplifiers, Cascoding Amplifiers and Multistage Amplifiers. Before starting the MOSFET Amplifiers, this class is like a revision of the previous MOSFET Amplifiers. In the paper called SSD, you have studied MOSFET. In the subject called SSD, you have studied MOSFET in the fourth and fifth modules. You have studied the structure of MOSFET, types of MOSFET, drain current equation of MOSFET, regions of MOSFET, linear region, saturation region. You have studied drain characteristics and transfer characteristics. You have studied short channel effect and channel length modulation. You can refer these basic things in the previous module. I am just going to give a brief content before moving to the syllabus. What is MOSFET? MOSFET stands for Metal Oxide Semiconductor Field Effect Transistor. We have classified transistors as BGT and FET. Junction Field Effect Transistor, MOSFET and Field Effect Transistor are examples of FET. MOSFET is a particular kind of Field Effect Transistor. When compared to BGT, MOS transistors can be made quite small. We can fabricate MOS transistors very small. Moreover, the fabrication process of MOSFET is very simple. It is very easy to fabricate MOSFET. In addition, MOSFET is used exclusively to implement digital logic and memory functions. The highest packing density and lowest power dissipation of MOSFET help to fabricate VLSI chips using this technology. We use MOSFET in VLSI chips. The highest packing density and lowest power dissipation of MOSFET help to fabricate VLSI chips using this technology. We are using MOSFETs in VLSI chips. We can classify MOSFET into two categories. Enhancement Mode MOSFET and Depletion Mode MOSFET. Enhancement Mode MOSFET and Depletion Mode MOSFET can be categorized into two categories. Enhancement Mode MOSFET and Depletion Mode MOSFET are classified based on the channel in MOSFET. The channel in MOSFET is called Depletion Mode MOSFET. There is a channel between drain and source. What happens when the channel is normal? A current conduction occurs in the MOSFET. That is Depletion Mode MOSFET. Enhancement Mode MOSFET has no channel in the MOSFET. That is why it is called Enhancement Mode MOSFET. There are two types of MOSFETs. P-type Enhancement Mode MOSFET and N-type Depletion Mode MOSFET. This figure shows the physical structure of an Enhancement Mode MOSFET. This transistor is fabricated in a P-type substrate. This substrate is a single crystal silicon wafer that provides physical support for the device. This figure shows two heavily doped N plus regions. These N plus regions are the source and drain regions of the MOSFET. MOSFET has a terminal called Source, Drain, Gate, Bulk or Body. This figure shows a thin layer of silicon dioxide. This silicon dioxide acts as an excellent electrical insulator. This is the Source and Drain terminal. This figure shows metals deposited on the top of the oxide layer. These metals are used to form gate electrodes. Metal Oxide Semiconductor Field Effect Transistor Silicon Gate Technology Insulated Gate Field Effect Transistor Enhancement Mode Enhancement Type P MOSFET Threshold Voltage Enhancement Type N MOS Enhancement Mode MOSFET