A fast recovery diode and its manufacturing method

Abstract

The invention relates to a power semiconductor device and a manufacturing method thereof and specifically to a fast recovery diode and a manufacturing method thereof. A junction pushing is performed in an active region in order to form a P+ region and a P region. A junction forming process comprises: firstly performing boron injection in order to push a junction one to ten [mu]m; secondly performing phosphorus compensative injection, wherein a phosphorus injection condition requires that the amount of injected phosphorus only decreases the concentration of the P region close to the silicon surface but not reverses a junction; and performing active region compensative injection to form the P region with low surface concentration. Therefore, the amount of hole injection of the P region in forward conduction is decreased while the concentration on the two sides of a PN junction is guaranteed. When minority carrier lifetime control is used, excessive recombination centers are not required to be generated. Therefore, a series of parameters are optimized. The fast recovery diode and the manufacturing method thereof perform phosphorus compensative injection on the P region so as to achieve the decrease in the surface concentration of the P region. Therefore, the decrease in the number of the hole injection in forward conduction is actually achieved.

Description

technical field [0001] The invention relates to a power semiconductor device and a manufacturing method thereof, in particular to a fast recovery diode and a manufacturing method thereof. Background technique [0002] When a PIN diode conducts forward current, it generally injects a large number of carriers from the anode (P region) and cathode (N+ region) to the drift region (I region), and the hole carriers injected from the anode form a minority in the drift region. store charge in the form of . The minority carrier injection causes the conductance modulation effect in the drift region, thereby reducing the forward on-state voltage drop, which is the biggest advantage of both PIN diodes and bipolar devices. When a reverse voltage is suddenly applied to the conducting diode, the device will not be turned off immediately because a large number of minority carriers are stored in the drift region during conduction. Only when these minority carriers are completely extracted ...

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Problems solved by technology

[0004] 1. Electron irradiation will lead to a large leakage current of the device. Due to the global irradiation, electromagnetic interference (EMI) will be generated during fast di / dt switching; after the device is used for 1-2 years, the defect of electronic irradiation will gradually Recovery, the recovery speed becomes slower, the device characteristics degrade, and the hidden danger of failure is brought to the circuit;

[0005] 2. Au and Pt are commonly used for heavy metals. Au is only used in low-voltage devices below 600V due to its large leakage current; Pt is a good choice for low-voltage devices, but due to the P-type doping effect of Pt, it requires high For devices with resistive materials, the Trr parameter is difficult to control, and may even lead to device inversion

[0006] 3. In order to obtain a fast recovery diode that meets the recovery speed requirements, it is often achieved by increasing the number of recombination centers, that is, increasing the electron irradiation dose or metal doping temperature, but this will bring reverse leakage and forward on-state voltage. The increase of drop Vf and the decrease of avalanche tolerance

At the same time, because the holes participate in the conductance modulation, the voltage drop of the diode is reduced, but at this time the voltage drop has a negative temperature coefficient, and the product is not easy to be connected in parallel, which is not conducive to the application of high-current circuits.

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