MOSFET Selection | N-Channel MOSFET Construction Principles

Metal-Oxide-SemIConductor structure of the crystal transistor commonly known as MOSFET, where MOSFETs are divided into P-type MOSFETs and N-type MOSFETs. The integrated circuits composed of MOSFETs are also called MOSFET integrated circuits, and the closely related MOSFET integrated circuits composed of PMOSFETs and NMOSFETs are called CMOSFET integrated circuits.

A MOSFET consisting of a p-type substrate and two n-spreading areas with high concentration values is called an n-channel MOSFET, and the conductive channel caused by an n-type conductive channel is caused by the n-spreading paths in the two n-spreading paths with high concentration values when the tube conducts. n-channel thickened MOSFETs have the n-channel caused by a conductive channel when a positive directional bias is raised as much as possible at the gate and only when the gate source operation requires an operating voltage exceeding the threshold voltage. n-channel depletion MOSFETs are those that are not ready to the gate voltage (gate source operation requires an operating voltage of zero). An n-channel light depletion MOSFET is an n-channel MOSFET in which the conductive channel is caused when the gate voltage (the gate source operating requirement operating voltage is zero) is not prepared.

NMOSFET integrated circuits are N-channel MOSFET power supply circuit, NMOSFET integrated circuits, the input resistance is very high, the vast majority do not have to digest the absorption of power flow, and thus CMOSFET and NMOSFET integrated circuits connected without having to take into account the load of power flow.NMOSFET integrated circuits, the vast majority of the selection of a single-group positive switching power supply circuit power supply circuits The majority of NMOSFET integrated circuits use a single positive switching power supply circuit power supply circuit, and to 9V for more. CMOSFET integrated circuits only need to use the same switching power supply circuit power supply circuit as the NMOSFET integrated circuits, can be connected with NMOSFET integrated circuits immediately. However, from NMOSFET to CMOSFET immediately connected, because the NMOSFET output pull-up resistance is less than the CMOSFET integrated circuit keyed pull-up resistance, so try to apply a potential difference pull-up resistor R, the value of the resistor R is generally 2 to 100KΩ.

Construction of N-channel thickened MOSFETs
On a P-type silicon substrate with a low doping concentration value, two N regions with a high doping concentration value are made, and two electrodes are drawn out of aluminum metal to serve as the drain d and the source s, respectively.

Then in the semiconductor component surface masking a very thin layer of silica insulating tube, in the drain - source insulating tube between the drain and source of another aluminum electrode, as the gate g.

In the substrate also lead out an electrode B, which consists of a N-channel thick MOSFET. MOSFET source and substrate are generally connected together, the vast majority of the pipe in the factory has long been connected to it, its gate and other electrodes are insulated between the casing.