The full English name of NMOS is: N-Mental-Oxide-Semiconductor. It means metal-oxide-semiconductor, and transistors with this structure are called MOS transistors. There are P-type MOS tubes and N-type MOS tubes. An integrated circuit composed of MOS tubes is called a MOS integrated circuit. A circuit composed of NMOS is an NMOS integrated circuit. A circuit composed of PMOS tubes is a PMOS integrated circuit. A complementary MOS circuit composed of NMOS and PMOS tubes is a CMOS circuit. .
PMOS refers to an n-type substrate, p-channel, and a MOS tube that relies on the flow of holes to carry current. Full name: positive channel Metal Oxide Semiconductor
Alias: positive MOS
Metal oxide semiconductor field effect (MOS) transistors can be divided into two categories: N-channel and P-channel. P-channel silicon MOS field-effect transistors have two P+ regions on the N-type silicon substrate, respectively. It is called the source and the drain. There is no conduction between the two poles. When sufficient positive voltage is applied to the source (the gate is grounded), the N-type silicon surface under the gate presents a P-type inversion layer, which becomes the connection between the source and the drain. Extreme channel. Changing the gate voltage can change the electron density in the channel, thereby changing the resistance of the channel. This kind of MOS field effect transistor is called a P-channel enhancement type field effect transistor. If there is no gate voltage applied to the surface of the N-type silicon substrate, there will already be a P-type inversion layer channel. Adding an appropriate bias voltage can increase or decrease the resistance of the channel. Such MOS field effect transistors are called P-channel depletion field effect transistors. Collectively called PMOS transistors. The hole mobility of P-channel MOS transistors is low, so when the geometric size of the MOS transistor and the absolute value of the operating voltage are equal, the transconductance of the PMOS transistor is smaller than that of the N-channel MOS transistor. In addition, the absolute value of the threshold voltage of P-channel MOS transistors is generally high, requiring a higher operating voltage. The voltage and polarity of its power supply are incompatible with bipolar transistor-transistor logic circuits. PMOS operates at a lower speed due to its large logic swing, long charging and discharging process, and small device transconductance. After the emergence of NMOS circuits (see N-channel metal-oxide-semiconductor integrated circuits), most of them have been used by NMOS circuits. replace. However, because PMOS circuit technology is simple and cheap, some medium- and small-scale digital control circuits still use PMOS circuit technology. MOSFET has three pins, usually G, D, and S. By adding a control signal between G and S, the conduction and cutoff between D and S can be changed. PMOS and NMOS are completely similar in structure. The only difference is the doping type of the substrate and source and drain.