The personal behavior of silicon carbide diodes is more like an idealized power switch than PN junction components. The two most important performance parameters of a Schottky diode are its low reverse recovery positive charge (Qrr) and its repair softening coefficient. With low Qrr, when the diode operating voltage is changed to the reference point in the reverse direction, the time required for the turn-off process, that is, the reverse recovery time trr is greatly shortened. The following lists the Schottky diode trr below 0.01 between each other. Conducive to high-frequency applications, there are materials detailing its output power up to 1MHz (also reported to reach 100GHz). The high softening coefficient will reduce the EMI noise caused by the diode turning off, and reduce the influence of the actual operation of the speed control.
Silicon carbide diodes also have an excellent index value than PN junction components, which is to guide the power supply to be lowered and have low on-off loss. Silicon carbide diodes also have two defects. One is that the reverse voltage VR is low, generally only about 100V; the other is that the leakage current IR in the reverse direction is very large.
Silicon carbide diode is a metal material made of precious metals (gold, silver, aluminum, platinum, etc.) A is the positive stage, and the N-type semiconductor B is the negative stage. The potential barrier generated on the surface of the two is used as a metal material-semiconductor. Components. Since there are many electronic devices in N-type semiconductors, and there are only a small amount of free charge in precious metals, the electronic devices diffuse from B with high concentration to A with low concentration. Obviously, there is no cavitation in the metal material A, and there will be no fitness exercise from A to B. As the electronic devices continue to diffuse from B to A, the concentration of electronic devices on the surface of B slowly decreases, and the surface charge balance is destroyed, so a potential barrier is generated, and the electric field direction is B→A. However, in the effect of the electrostatic field, the electronic devices in A will also cause the drifting fitness exercise from A to B, thereby weakening the electrostatic field generated by the external diffusion fitness exercise. When a space charge zone with a certain total width is created, the electronic device drift caused by the electrostatic field and the fitness exercise caused by the difference in the concentration value of the electronic device are relatively balanced, which creates a Schottky barrier.
The typical Schottky rectifier internal power circuit structure is based on an N-type semiconductor as a substrate, and an N-epitaxial layer with arsenic as a dopant is formed on it. Anodizing uses raw materials such as molybdenum or aluminum to make a barrier layer. Use silicon dioxide (SiO2) to remove the electrostatic field in the edge area and increase the pressure resistance of the water pipe. The N-type substrate has a small on-state resistor, and its inclusion concentration is 100% higher than that of the H-layer. An N+ negative electrode layer is generated under the substrate, which has the effect of reducing the loop resistance of the negative electrode. According to the main parameters of the optimized structure, a Schottky barrier is generated between the N-type substrate and the anodized metal material, as shown in the figure below. When forward bias is applied on both sides of the Schottky barrier (positive level for anodized metal material and negative level for the N-type substrate), the Schottky barrier layer becomes smaller and its internal resistance decreases; on the contrary, , If the reverse bias is applied on both sides of the Schottky barrier, the Schottky barrier layer becomes larger and its internal resistance increases.
The above explained is the difference between the principle of silicon carbide diode and Schottky rectifier. I hope it will be helpful to you after reading it. If you want to learn more about silicon carbide diodes, please contact customer service online or Call the company's service hotline (upper right corner of the website) for consultation, we will be happy to provide you with quality service!