ECT 2440 Chapter Notes - Chapter 12: Current Source, Pmos Logic, Threshold Voltage
Document Summary
The n-channel enhancement-mode mosfets or nmos transistors are silicon crystal chips with impurities added to various regions to produce n-type and p-type material. In n-type material, conduction is due mainly to negatively charged electrons. In p-type material, conduction is due mainly to positively charged holes: the device terminals of an nmos transistor include the drain (d), gate (g), source (s), and body or substrate (b). In normal operation, negligible current flows through the body terminal. The gate is insulated from the substrate by a thin layer of silicon dioxide and negligible current flows through the terminal. When a sufficiently large (positive) voltage is applied to the gate relative to the source, electrons are attracted to the region under the gate, and a channel of n-type material is induced between the drain and the source. If voltage is applied between the drain and source, current flows into the drain through the channel and out the source.
