Soft fast recovery diode of multi-mixture structure and preparation method thereof

Abstract

The main purpose of the present invention is to provide a high-voltage soft fast recovery diode and its preparation method. This method adopts the Schottky mixed high and low concentration PN junction structure, and simultaneously manufactures the variable doping planar terminal (VLD) protection, which improves the breakdown voltage. And anti-surge ability, reduce the recovery time, form soft recovery characteristics, and achieve good low leakage effect. The present invention arranges at intervals on the N- / N / N+ type silicon chip to produce high-concentration P+ / N-junction, Schottky junction, low-concentration P- / N-junction, Schottky junction structure, by increasing P- / N-structure, which reduces the hole injection efficiency, reduces the reverse recovery time, and avoids the disadvantage of reducing the Schottky junction barrier height, achieving the combination of soft and fast recovery and low leakage; and P- / N-junction At the same time, forming a VLD terminal structure ensures high voltage and high anti-surge capability, and simplifies the manufacturing process and reduces costs. Compared with the fast recovery diodes of traditional PIN and MPS structures, the multi-hybrid structure diode of the present invention has faster recovery time and wider application range.

Description

technical field [0001] The invention belongs to the technical field of diodes and their preparation, in particular to a high-voltage, soft and fast recovery diode and its preparation method. Background technique [0002] In power electronics, switching power supply circuits, and various motor drive circuits, higher and higher operating frequencies will greatly reduce the volume of passive components (inductors and capacitors) and the power loss on them, but for the components used in the circuit High-power switching diodes require shorter reverse recovery time and lower switching losses. At present, fast recovery and ultra-fast recovery diodes with PIN structure are still the most widely used in these circuits. However, ordinary PIN diodes do not have reverse soft recovery characteristics. During the reverse recovery process, there will be a large reverse peak recovery current and reverse peak voltage, which will increase the loss and electromagnetic interference (EMI) of t...

AI Technical Summary

Problems solved by technology

like figure 1 The structure shown, this structure can improve the soft recovery characteristics, but if you want to achieve faster recovery characteristics, you must increase the P+ junction spacing, which will lead to a weakened shielding effect on the Schottky junction and an increase in the reverse leakage current; the P+ junction spacing is small, too many carriers are injected into the drift region, which reduces the speed

At the same time, for the improvement of the reverse avalanche surge capability of high-power high-voltage fast recovery diodes, the terminal protection of the chip is very important. The commonly used voltage divider ring structure has the disadvantage of low ability to generate dynamic current wires, and the variable doping extended terminal technology ( VLD) has been proven to effectively improve the ability to resist avalanche breakdown, but the manufacturing process needs to increase the injection of low-concentration P-type impurities, which increases the number of steps. In view of the above problems, the present invention provides a multi-hybrid structure soft fast recovery diode and its preparation method, this method adopts the Schottky mixed high and low concentration PN junction structure, and simultaneously manufactures the variable doping planar terminal (VLD) protection, which improves the breakdown voltage and anti-surge capability, reduces the recovery time, forms soft recovery characteristics, and Good low leakage effect can be achieved

Images