| 3.1 Basic MOSFET Structure |
| In the introduction to a system, we got an overview of various levels of design, viz. Architectural level design, Program level design, Functional level design and Logic level design. However we can't understand the levels of design unless we are exposed to the basics of operation of the devices currently used to realize the logic circuits, viz., MOSFET (Metal Oxide Semiconductor Field Effect Transistor). So in this section, we'll study the basic structure of MOSFET. |
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| The cross-sectional and top/bottom view of MOSFET are as in figures 3.11 and 3.12 given below : |
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Fig 3.11: Cross-sectional view of MOSFET |
Fig 3.12: Top/Bottom View of MOSFET |
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| An n-type MOSFET consists of a source and a drain, two highly conducting n-type semiconductor regions which are separated from the p-type substrate by reverse-biased p-n diodes. A metal or poly crystalline gate covers the region between the source and drain, but is isolated from the semiconductor by the gate oxide. |
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