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Semiconductor device

A semiconductor and carrier technology, applied in the field of diodes, can solve the problem that the rising slope of the reverse current waveform cannot obtain soft switching characteristics, etc.

Active Publication Date: 2020-02-07
SANKEN ELECTRIC CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] However, there is a problem that when the reverse recovery time is shortened by introducing crystal defects, the rising slope of the reverse current waveform becomes steep and soft switching characteristics cannot be obtained.

Method used

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  • Semiconductor device
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Examples

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Embodiment 1

[0028] The structure of the diode of Example 1 will be described. Such as Figure 4 As shown, the diode of the present invention has a plurality of carriers with a higher impurity concentration than the drift layer inside the drift layer in the outer peripheral region of the depletion layer region formed when a reverse bias is applied, and in the lower part of the channel stopper ring. Accumulation layer (N+ layer). The impurity concentration of the carrier storage layer increases stepwise from the device center side to the device end side. When the concentrations in the direction from the device center side to the end part side are a, b, and c, a figure 1 1) slows down, so that the current waveform can be softened. In addition, in order to soften the switching waveform, it is desirable to arrange the carrier storage layers in a long strip shape in parallel from the center side of the device toward the edge side.

[0029] In addition, it is desirable that the impurity conce...

Embodiment 2

[0032] The structure of the diode of Example 2 will be described. Such as Figure 5 As shown, in Example 2, a crystal defect layer functioning as a lifetime control body is formed in a band shape below the anode diffusion layer (P+ diffusion layer) of the diode. In this way, crystal defects functioning as lifetime controllers are introduced in bands between the anode diffusion layer (P+ diffusion layer) and the carrier storage layer. Compared with the case of introducing lifetime controllers throughout the device, , which can further soften the switching waveform. The reason is that, when the lifetime control body is introduced as a whole, the carriers other than the region discharged by the depletion layer will also disappear. However, by locally forming a layer with a short lifetime directly under the anode, the Since the disappearance of carriers can be locally suppressed, the effect of softening can be further obtained.

[0033] In addition, based on this structure, whe...

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Abstract

The invention provides a semiconductor device for moderating the switching waveform of a high-speed diode.A semiconductor device has a PiN diode structure which passes current in a longitudinal direction. A plurality of carrier accumulation layers (N+ layers) 11 which have concentrations different from each other are arranged in a region of a drift layer outside a depletion layer region formed when reverse bias is applied. The carrier accumulation layers are arranged from the device center side toward the end side; and concentrations of the carrier accumulation layers are gradually increased from the device center side toward the end side. The plurality of carrier accumulation layers control extension of the depletion layer region.

Description

technical field [0001] The present invention relates to diodes with high-speed switching characteristics and soft switching characteristics. Background technique [0002] In recent years, switching diodes used for high-frequency rectification have been required to increase their speed. In order to increase the speed of the diode, it is necessary to shorten the life time of the carriers in the semiconductor element to shorten the reverse recovery time of the current. As the method, the following methods are known. Radiation irradiation, etc., introduces crystal defects that function as lifetime controllers, shortening the reverse recovery time. [0003] Patent Document 1: Japanese Patent Laid-Open No. 210-109031 Sanken Electric [0004] However, there is a problem that when the reverse recovery time is shortened by introducing crystal defects, the rising slope of the reverse current waveform becomes steep, and soft switching characteristics cannot be obtained. Contents of...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01L29/868H01L29/06
Inventor 森川直树
Owner SANKEN ELECTRIC CO LTD