Application advantages of Schottky diodes in circuits

Application advantages of Schottky diodes in circuits

Schottky diodes is a semiconductor component made of metal materials as the positive stage and N-type semiconductor as the negative stage, which uses the potential barrier generated on the surface of both to have the characteristics of rectifier. It is a hot carrier diode. Schottky diode is mainly used as rectifier diode, Flyback diode, maintenance diode, etc. in the power circuit, and it is mainly used in the power circuit with low voltage and large current flow, such as power transformer, soft starter Inverter power supply, fiber optic communication. Widely used in small signal circuits in semiconductor radios, recorders, televisions, and communication devices, today we will take a look at the application advantages of Schottky diodes in circuits:

Schottky diodes

Schottky diodesis a metal material semiconductor component made of precious metals such as gold, silver, aluminum, platinum, etc., with positive stages and N-type semiconductor B as negative stages. The potential barrier generated on the surface of the two materials has the characteristics of a rectifier. Due to the presence of many electronic devices in N-type semiconductors, with only a small amount of free charge in precious metals, electronic devices diffuse from high concentration B to low concentration A.

If there is no cavitation in metal material A, there will be no outward diffusion of cavitation from A to B. As electronic devices continue to diffuse from B to A, the concentration value of B's surface electronic devices gradually decreases, and the surface charge balance is destroyed, resulting in the formation of a potential barrier with an electric field direction of B → A. However, within the effectiveness of this electrostatic field, the electronic devices in A can also cause a drifting exercise from A to B, thereby weakening the electrostatic field generated by external diffusion exercise. When a space charge zone with a certain total width is created, the movement of the electronic devices caused by the electrostatic field and the movement of the electronic devices caused by the external diffusion of different concentration values achieve a relative balance, and the Schottky barrier is generated.

The typical internal power circuit structure of Schottkyrectifier tube is to use N-type semiconductor as the substrate, on which an N-neneneba epitaxial layer with arsenic as the dopant is generated. Anodizing should use raw materials such as molybdenum or aluminum to make a barrier layer. Use silicon dioxide (SiO2) to remove static electricity in the edge area and improve the compressive strength of water pipes.

The N-type substrate has a small on state resistor, and its impurity concentration value is 100% higher than that of the H-layer. An N+negative electrode layer is generated below the substrate, which reduces the circuit resistance of the negative electrode. According to the main parameters of the optimized structure, Zottky barrier is generated between the N-type substrate and the anodized metal material, as shown in the following figure. When the forward bias voltage is added on both sides of the Schottky barrier (positive stage of the anodic oxidation metal material plug-in line, negative stage of the N-type substrate plug-in line), theSchottky barrier layer becomes smaller and its internal resistance shrinks; On the contrary, if the opposite bias voltage is added on both sides of the Schottky barrier, theSchottky barrier layer will become larger and its internal resistance will increase.